President Reagan's budget director, David A. Stockman, was a source for author Laurence I. Barrett's revelation that briefing papers "filched" from the Carter camp were used by Stockman to help prepare Reagan for his 1980 debate with Jimmy Carter, Stockman spokesman Edwin L. Dale Jr. said yesterday.

Responding to a Washington Post query, Dale said Stockman "confirmed that he did mention it to Barrett."

Dale said that what Stockman told Barrett, a Time magazine correspondent, was "faithfully recorded" in Barrett's recently published book on Reagan, "Gambling With History." Its one-paragraph account of Stockman's use of the Carter documents led to the controversy that has caused concern in the Reagan White House and has prompted Justice Department and congressional investigations.

A Reagan administration official also confirmed yesterday that on the day of the debate, Oct. 28, 1980, Stockman said at an Optimist Club luncheon in Casopolis, Mich., that he was helped in rehearsing Reagan by a "pilfered copy" of Carter's briefing book.

The official, who characterized Stockman's statement as "colorful language," said he thought it was made in a private conversation rather than in Stockman's formal luncheon speech, as was reported at the time by The Elkhart, Ind., Truth newspaper.

Stockman reiterated in an interview yesterday that he viewed the documents obtained by the Reagan camp as helpful to him alone in preparing for his role as a Carter stand-in during rehearsals of Reagan for the debate.

"I spent four days in intense rehearsals and preparation for the make-or-break debate," Stockman said. "All the heavy hitters-- Edwin Meese, James A. Baker, William J. Casey, Richard Wirthlin and Michael K. Deaver--were serving up their most profound and intimate pearls of wisdom on tactics, positioning, debate lines, rebuttals. Not once was there a mention, hint or even a whiff of a suggestion that people were using this big pile of Carter papers or drawing on inside knowledge from the Carter campaign. I'll swear to that on a stack of Bibles.

"The only person I can imagine this stuff was useful to was the guy who had to digest in one day the entire sorry history of the Carter administration," Stockman said.

Baker, Reagan's chief of staff, said yesterday that White House officials would "cooperate fully" with a widened congressional inquiry into how the Reagan campaign committee obtained the documents prepared by Carter's staff.

The broadened inquiry was announced by Rep. Donald J. Albosta (D-Mich.), who said his Post Office and Civil Service subcommittee on human resources is considering whether to issue subpoenas and hold public hearings. The question of how the Carter documents came into the possession of the Reagan campaign also is being investigated by the Justice Department at the request of the White House.

White House communications director David R. Gergen said yesterday that a search of files to determine whether Reagan officials had any more documents from the Carter camp was continuing.

"The White House has turned over to Justice all relevant and appropriate materials that we've been able to find," Gergen said.

Despite Stockman's statement that he was the only person in the Reagan campaign to benefit from the Carter documents, one administration official said yesterday that some of the material from them was incorporated into briefing material sent to Reagan's campaign residence in Wexford, Va., where his team of advisers was preparing for the debate.

This official did not say specifically that Reagan was given the material. Other officials who were close to the briefing process said it was unlikely that any of the papers were given to Reagan.

As part of his broadened investigation, Albosta said he has sent inquiries to U.N. Ambassador Jeane J. Kirkpatrick and Frank Hodsoll, chairman of the National Endowment of the Arts, regarding their roles in preparing Reagan for the debate. Similar inquires were sent previously to Baker, Stockman, Gergen and Casey, Reagan's campaign chairman, who is now director of the CIA.

Stockman and Gergen joined Baker yesterday in pledging cooperation with Albosta's investigation. But a CIA spokesman said Casey was out of town, could not be contacted and would not comment on the investigation. Unlike the other Reagan aides, Casey has refused comment consistently.

Baker said in a letter to Albosta that "to his best recollection" the Carter documents were given to him by Casey. But Casey said in his own letter to Albosta that he did not remember seeing or passing them along.

Administration officials said yesterday that they had failed in attempts--including a meeting Baker had with Casey on Sunday--to refresh the CIA director's recollection, and that Casey said he does not recall where the documents came from.

President Reagan, in his news conference Tuesday night, defended Casey's lack of recollection. "I can understand his very well not having paid any attention," Reagan said. "He wasn't going to wade through a stack of papers. They didn't come in a binder or anything."

Because of Casey's lack of recollection, administration officials said, they have been stymied in their efforts to locate the Reagan campaign's source for the Carter documents.

"It may be, if we find out who the mole is in the Carter camp , that the mole will tell us perhaps how or why he or she might have taken those documents," Albosta told a crowded news conference on Capitol Hill yesterday. "We need to know whether the person who removed those documents was a civil servant or a high-ranking official in the Carter administration."

Albosta's normally obscure subcommittee, which has five professional staff members, has arranged to borrow several investigators from its parent committee to pursue the highly publicized case.

Albosta said he wants to learn whether the Reagan campaign received other materials from the Carter White House, what kind of relationship the two campaigns had with the materials' source, and whether federal ethics laws should be changed to prevent such incidents.

He said the matter could involve criminal violations, even if the person who leaked the Carter materials had legal access to the documents. "If someone had promised someone that . . . they would get a job from this, that's a clear violation of the law," he said.

Adding that he would refer any evidence of criminal wrongdoing to the Justice Department, Albosta said, "They're the ones that should appoint a special prosecutor or investigate it themselves . . . . The president can make it easy for us" by demanding that his aides voluntarily divulge all the details.

Rep. Thomas A. Daschle (D-S.D.) added that he believes there are White House officials "who simply haven't come forward with the truth in this matter." No Republican members attended the news conference.

At the White House, officials said they had become frustrated by what has turned into "a national story" despite several days of minimizing its importance. They said their search of files turned up nothing new yesterday.

One official said Stockman didn't know what happened to the documents he used in preparing for the debate. He speculated that they may have been thrown out when Stockman moved from Capitol Hill to his present quarters in the Old Executive Office Building. The hundreds of pages of Carter documents released by the White House Tuesday came from the files of Gergen and Hodsoll.

Stockman spoke at length about the papers at the Optimist Club luncheon in Casopolis on the day of the 1980 debate, according to the Elkhart newspaper, which described him as regaling his luncheon audience with predictions of what Carter would say on various issues and how Reagan would answer him.

Stockman, then a Michigan congressman, was reported as explaining that he had played the role of Carter in Reagan's debate rehearsals and had used a "pilfered copy of the briefing book he Carter was going to use."

"Stockman outlined the 'white lies' Carter was going to center on in the debate," the newspaper reported. "Apparently the Reagan camp's 'pilfered' goods were correct, as several times both candidates said almost word for word what Stockman predicted."

The article, written by the newspaper's Michigan correspondent, Dee Bourdon, created no stir. The Elkhart Truth played it on page 15, and did not mention Stockman's claim of having "pilfered" Carter documents until midway through the story.

"If that Elkhart story had been carried by the wire services on the day after the debate, would Ronald Reagan be president today?" former Carter pollster Patrick Caddell asked yesterday.

Barrett reported in his book that "Apparently a Reagan mole in the Carter camp had filched papers containing the main points the President planned to make when he met Reagan for the debate."

Dale said yesterday that Stockman said he never mentioned the term "mole" to Barrett, but that he had used "filched."

"He has used 'filched' and 'pilfered' as colorful language," Dale said. "He didn't know and doesn't know how they the Carter documents got into the Reagan campaign."