The CIA has been making an awful lot of mistakes lately.

At least that's what its censors have been telling Ralph McGehee, a bemedaled veteran of 25 years with the agency who retired in disillusionment in 1977.

Until Adm. Bobby Ray Inman, deputy CIA director, stepped in, the censors appear to have been trying to "reclassify" information so old and so widely published it isn't even secret any more.

One example is the existence of Camp Peary, the CIA school for spies known as "The Farm" near Williamsburg, Va., where thousands of agency recruits have received clandestine training. The camp has been mentioned in numerous books and articles in the past decade, including writings cleared by the CIA.

The agency's Publications Review Board, however, told McGehee Feb. 16 that even an allusion to "nearby Williamsburg" was "classified and must be deleted" from a book chapter he had completed. The board also insisted he drop all mention of the size of his Camp Peary class (approximately 30) back in the '50s, the kind of training they got, and a memorable incident involving the booby-trapping of a toilet seat with a military firecracker.

"Classified," McGehee was informed.

Stunned, he wrote back in protest that many of the items in question had come from an earlier, CIA-cleared manuscript he had written, other bits of information had been contained in other CIA-cleared books, and still others had been widely published in writings that were not cleared by the agency. Essentially, McGehee was submitting his work again because he had found a publisher and was in the process of rewriting and revising it. He had already gotten the original version past the agency's censors in 1980 after laborious haggling. Now he was being told that those censors had made one mistake after another.

The same argument has been used by several other government agencies this year in efforts to recall and suppress information already released. Administration officials are seeking explicit authority to do that in a new executive order under consideration at the White House.

McGehee was especially upset over the review board's demand that he abandon several pages dealing with psychological tests the agency gives to find people who are, for instance, "logical and literal, seeing the world in ordered 'blacks' and 'whites' " and who have "difficulty in situations requiring sensitivity, sympathy and insight."

As recently as last October, he pointed out, the board's legal adviser had explicitly cleared a speech McGehee submitted in which he dealt with those same tests and described them as "designed to identify for hiring only those with rigid outlooks, predetermined bias, and authority-respecting, nonquestioning attitudes." In addition, he said, the review board had repeatedly ruled that the topic was not classified.

"This is the first time I know of their CIA's reversing a previous determination," said McGehee's lawyer, Mark H. Lynch. "This is clearly evidence that the Publications Review Board is likely to be less cooperative with authors."

Under existing rules, neither the CIA nor any other government agency has the authority to "reclassify" information already declassified. The classification system currently in effect, promulgated by President Carter in 1978, specifically states:

"Classification may not be restored to documents already declassified and released to the public under this order or prior orders."

McGehee says that when he brought this to the attention of a CIA legal adviser last month, the lawyer told him, "Oh, we're operating under a new order."

A draft executive order, under consideration at the Reagan White House, would wipe out the Carter proviso and allow officials to "reclassify information previously declassified and disclosed if it is determined in writing that (1) the information requires protection in the interest of national security and (2) the information may reasonably be recovered."

President Reagan, however, has yet to put any new rules into effect.

McGehee said the CIA lawyer quickly realized that and shifted instead to the position that agency officials had, again and again, "made a mistake in declassifying" the details in his original manuscript.

Inman reversed the board's decision in every instance this month after McGehee and his lawyer submitted documentation for their claims about prior release and publication. But McGehee is still fearful that the censors are going to hold him off on the rest of his book until the new executive order is issued.

For instance, he says, he just got a letter from the review board's lawyer rejecting his entire second chapter because "the items of classified information were so numerous and interwoven with the text that if they were to be deleted, the remaining text would not be intelligible."

McGehee, whose work at the agency was capped by award of the Career Intelligence Medal, was baffled. "Most of that chapter deals with my personal life in a certain country, traveling around, sightseeing and so forth," he said. "The guts of what I was doing in that country had already been cleared for me, in a job resume saying this was the type of activity I was engaged in."