The conservative battle cry these days is "Let Reagan Be Reagan," the code words for the suggestion that the president is being protected by his White House staff from indulging in his own best inclinations and from saying what he really means.

It is time to acknowledge that the right wing, despite high-pitched overstatements of the case, has a valid point. On nearly every issue of consequence that arose on the president's eclectic California trip last week, there was a signal, or a series of signals, from communications and press officials that undercut Reagan's position.

This is true on the controversy swirling around Environmental Protection Agency Administrator Anne M. Burford, a subject addressed elsewhere in this newspaper today. But it is equally true, or more so, on the even more vital question of U.S. policy in El Salvador.

After a senior administration official early in the week told this reporter that the president was prepared to take "all necessary measures" to see that El Salvador does not fall into leftist hands, White House spokesman Larry Speakes came forward the following day to term this comment an "unfortunate remark" and leave the impression that Reagan is more conciliatory than he actually is.

In fact, the senior official was understating. When Reagan was asked about El Salvador at a luncheon forum in San Francisco two days later, he responded with a militant declaration that expresses his true views, saying that El Salvador "is on the front line in a battle that is really aimed at the very heart of the Western Hemisphere and eventually at us."

In the president's view, as El Salvador goes, so goes Texas. He ticked off the countries he thought would fall after a communist takeover of El Salvador: "Costa Rica, Honduras, Panama, all of these would follow," he said. As Reagan sees it, this would mean that U.S. commerce through the Panama Canal and the Caribbean would be imperiled.

Before the luncheon, Speakes told reporters that Reagan had made no decision on whether to increase the number of U.S. advisers used for training Salvadoran troops. It may be true that Reagan hasn't signed any formal decision memorandum, but there is no question about where the president stands on the issue of advisers.

In his answer to the question about El Salvador at the luncheon forum, the president said "we may want to go beyond" the present limit of 55 advisers. Afterward, in private meetings with his secretaries of state and defense, he was even more outspoken.

"If you thought he was militant at lunch, you should have heard him later in the afternoon," one administration official said.

In private, Reagan is determined "not to lose El Salvador on his watch," as one official put it. It is the same message Reagan also gives in public when the signal is not filtered through his communications apparatus.

This week, after negotiations with Congress that administration officials regard as crucial, Reagan hopes to be able to announce a bipartisan plan for bolstering the Salvadoran government. It is hard to understand how the president's goals are served by aides who try to disguise his true position on what he sees as the communist danger in Central America.

While Reagan was on the road last week, communications director David R. Gergen was in New York and a rumor circulated in the traveling party that he was exploring the possibility of a network television job. Gergen says he was spending a day at ABC News to see how an evening news program is put together.

Like some others in the electronic-oriented Reagan White House, Gergen is fascinated with the mechanics and decision-making processes of television and the ways it can be influenced.

Gergen said it would be "inappropriate" for him to use his position as a springboard for employment with the network or any other communications operation that covers the White House. He said he was not engaged in doing do. He did not rule out leaving the White House at some undefined future date for an academic position, which he said has always been a possibility.

The free traders in the administration are delighted with Reagan's anti-protectionism speech to the Commonwealth Club in San Francisco last week. They believe his free-trade inclinations have been muted by the recession and its effect on the auto and steel industries. Now that the economy appears to be improving, Reagan is said to feel free to speak out against protectionism, a view he has held for 50 years.

Reaganism of the Week: Speaking to lumber executives in Klamath Falls, Ore., about adding land to wilderness areas: "And if there is definite reason from an esthetic and--the uniqueness of the land, a standpoint to do that, to add that to the wilderness, fine; but not to go out on the wholesale amounts that they are talking--because that wasn't the intention and the private sector has not been guilty of rape of all the natural resources. There is today in the United States as much forest as there was when Washington was at Valley Forge."