The Reagan administration has begun internal discussions of whether President Reagan in his Nov. 19-20 summit meeting with Soviet leader Mikhail Gorbachev should broach possible limitations on "Star Wars" defense in return for Moscow's approval of deep cuts in the superpowers' offensive nuclear forces.

Administration sources said Reagan is far from a decision on this central issue in the U.S.-Soviet dialogue, whether to limit his plan for a strategic defense against nuclear missiles. Although some U.S. strategists favor swapping Star Wars restrictions for deep cuts, others -- particularly in the Defense Department -- have adamantly opposed such a deal.

With a little more than nine weeks left before the first U.S.-Soviet summit meeting in over six years, perhaps the most surprising thing emerging from interviews with several officials is that Reagan's approach to this linchpin arms issue is still unknown.

The impending U.S. visit of the new Soviet foreign minister, Eduard Shevardnadze, may have an important bearing on the outcome. Soviet sources said Shevardnadze, who is due to arrive in New York late this week, is expected to bring details of Moscow's arms control proposals to Reagan and Secretary of State George P. Shultz. Related story, Page A17.

Officials said a second round of high level U.S.-Soviet talks, either in a second Shevardnadze visit to the United Nations in October, or in a Shultz trip to Moscow before the November summit, is a possibility.

A U.S. survey team of White House and State Department officials is in Geneva this weekend to discuss U.S.-Soviet procedures and arrangements for the nine hours of talks planned for Reagan and Gorbachev, who will be accompanied only by a few top advisers.

A separate U.S. negotiating team left Washington yesterday for the third round of U.S.-Soviet bargaining sessions on nuclear and space arms due to begin Thursday and end just before the summit. What happens in the Geneva arms talks in the next two months is likely to have a big impact on the Reagan-Gorbachev discussion.

A State Department study of the 11 previous U.S.-Soviet summit meetings indicates that the most positive results emerged from decisions and diplomatic discussions in the two months preceding the summits, rather than at the meetings themselves or in follow-up sessions. Thus, preparations for the November meeting are entering their most crucial period, if history is a guide, with considerable uncertainty about what Reagan, and to a lesser extent Gorbachev, will do and say.

In preparation for the summit, Reagan has begun chairing weekly National Security Council meetings on summit topics, officials said. He has also been given six in a planned series of 25 "foundation" papers on Soviet history and society.

Administration officials have in mind truly dramatic cuts in offensive nuclear forces on the part of the Soviet Union and United States as the quid pro quo for any limitations that might be imposed on strategic defensive activities. Senior officials have talked about cuts in offensive forces well beyond the 30 to 40 percent range being publicly discussed as an important part of any tradeoff. Whether the Soviets would go along with such an approach is unknown.

Because of the gridlock over arms-control proposals in Reagan's first term and the persistent lack of bureaucratic discipline, any serious discussion of arms control compromises with the Soviets will have to take place among a highly restricted group of officials at the very top. Few memos are going to be circulated suggesting compromise, said a senior official who nevertheless expressed the belief that Reagan will hear a full range of opinion from his closest advisers about the arms control possibilities.

In this case, the key advisers are Shultz, Weinberger, White House national security affairs adviser Robert C. McFarlane, White House chief of staff Donald T. Regan and CIA Director William J. Casey. Many in the White House believe the first lady, Nancy Reagan, may also have an influence on her husband's thinking.

In public, the administration is seeking to dampen expectations that the Reagan-Gorbachev meeting will bring a breakthrough in U.S.-Soviet relations, which have reached a low point in the past five years.

High expectations, such as were generated by Gorbachev's Time Magazine interview and a subsequent meeting with U.S. senators, tend to build domestic and international pressure on Washington for compromises and, officials fear, could lead to a dangerous backlash in case of disappointment.

Privately, though, some officials said formulation of a U.S. plan to break the Geneva arms-talks deadlock through a defensive-offensive tradeoff to be discussed at the summit is a possibility at this stage of internal discussion. An official said Reagan has had discussions with top aides about the "concept" of limiting the Star Wars program.

Weinberger and his civilian aides at the Pentagon have opposed any such limitations. Shultz and his aides at the State Department are believed to favor at least giving serious consideration to the curbs.

Despite White House statements that Reagan's cherished Star Wars plan is not "a bargaining chip," a well-informed official said there is widespread agreement in the administration that "scaling down" the Strategic Defense Initiative in some way will be essential if any understanding with the Soviets on offensive arms is to be achieved. This point has been made repeatedly by former U.S. officials, arms-control experts, members of Congress and other outsiders familiar with the arms negotiations.

The issue of limitations on SDI is far more complex than it seems, involving such technical questions as the precise dividing lines between "research," which in its pure state cannot be monitored or safely limited by international negotiations, and "testing," "development" and "deployment," which are already supposed to be limited under the 1972 U.S.-Soviet Antiballistic Missile Treaty.

Whether and to what extent the ambitious space-based antimissile program would be effective cannot be known until the 1990s, long after Reagan leaves office, and this "research" phase grows longer as Congress consistently cuts the program by about one-third. The long gestation period adds to the uncertainty of present discussions but at the same time provides an opportunity for "interim restraints" on the Star Wars program that could be practical, relatively painless and would permit Reagan to say that research continues.

To a very large extent, the meeting with Gorbachev is Reagan's own enterprise -- it was he who decided to push for it early this year, despite misgivings on the part of several advisers. Thus the president's state of mind as he enters this decision-making period is unusually important.

A senior administration source who is not directly involved in summit preparation said Reagan has appeared to be increasingly sensitive to his historical legacy, especially following his brush with cancer this summer. The official believes Reagan could be prompted to move ahead with an arms trade-off if it is cast as the last chance for progress with the Soviets during his presidency.

But there is another side. The same official said Reagan also will be keenly aware that the Soviets will be looking for this kind of opening, hoping to exploit it. He predicted that those who don't want Reagan to give much ground at the summit -- he mentioned Weinberger and Casey -- will appeal to Reagan by saying that if he hangs tough, the Soviets will be back, but that to make a move at the summit out of concern for his own legacy would play into Moscow's hands.

"The first thing to remember is that this is a conservative administration, deeply suspicious of Soviet intentions," said a close observer of the White House maneuverings. The differences between the two nations, ideologies and political systems are so great, this official said, that "no quick or easy fixes are in sight."

Reagan has said repeatedly in public remarks and private instructions to aides that he hopes to spend considerable time at the summit on the fundamental aims and positions of the two nations and their political systems.

At times he has spoken as if he will use his first meeting ever with a general secretary of the Soviet Communist Party to show the Kremlin leader the error of his ways. In an interview with college students at the White House last week, for example, Reagan said he hopes to present in Geneva "facts to try and show them by deed, not word, that we are not an aggressor . . . . At the same time, I would like to reveal to them why we believe they represent a threat to us and to the western world."

Reagan added, "I don't know whether they are so indoctrinated with their policy of expansionism that they won't listen, but at least they will know where we're coming from and how we view things and what our determination is."

In addition to arms issues and ideology, the United States plans to use the summit discussions to touch on regional conflicts, U.S.-Soviet bilateral relations and human rights, all of which have been on the standard Reagan administration agenda in high-level meetings with the Soviets.

Surprisingly, the Soviet role in Afghanistan, which is generally considered the most intractable regional conflict, is under discussion within the administration as an area of possible progress in the Reagan-Gorbachev talks.

Reagan, for example, reportedly told state legislators in a closed meeting in Tampa Thursday that, if the Soviets removed troops from Afghanistan, it would be "a signal" for improved superpower relations.

A State Department official said speculation about possible Soviet movement in a positive direction on Afghanistan was "more of a seat-of-the-pants thing" than an idea based on clear-cut information. The costs of the drawn-out war in Afghanistan, of which there is no end in sight, seem to be coming home to Moscow increasingly, he said.

Another official pointed out that the Soviets had recently completed a brutal military offensive in Afghanistan and that there had been no sign of flexiblity from the Soviet-backed Afghan government in the most recent round of U.N.-sponsored talks on the issue in Geneva. Nevetheless, he added, there have been a few hints, especially to third parties, of a possible Soviet policy change.

A series of special U.S.-Soviet meetings on regional disputes was held earlier this year on Afghanistan, other Middle East issues, Southern Africa and East Asia. Before the end of the year, a similar meeting is likely on Latin-American issues.

These discussions have been led by an assistant secretary of state on the U.S. side and, typically, his counterpart in the Soviet Foreign Ministry. While considered worthwhile as an exchange of positions, the meetings have produced no sign of policy shifts.

Among the bilateral U.S.-Soviet matters being worked on for presentation at the Reagan-Gorbachev meeting are limited agreements on civil air transport, including the resumption of direct flights between the two nations, and a new cultural exchange agreement.

U.S. concerns about human rights in the Soviet Union are also to be presented to Gorbachev. A leading America-watcher in Moscow, Georgi A. Arbatov, said recently that Gorbachev in turn may bring up his concern about human rights in the United States.

One of the most consuming aspects of the internal discussions of the summit so far has been concentration at the White House about the public relations contest with Gorbachev, especially since the Soviet leader's Time interview. Reagan and many others in the government have expressed unhappiness at the seeming success of Gorbachev in portraying himself as reasonable and attractive. According to participants in the closed-door Tampa meeting, Reagan said of Gorbachev, with a trace of irritation, "He's got himself a pin-striped suit."