From this examination of JFK’s intentions on withdrawal, before his assassination:
https://www.bostonreview.net/articles/galbraith-exit-strategy-vietnam/
“Before a large audience at the LBJ Library on May 1, 1995, McNamara restated his account of this meeting and stressed its importance. He confirmed that President Kennedy’s action had three elements: (1) complete withdrawal “by December 31, 1965,” (2) the first 1,000 out by the end of 1963, and (3) a public announcement, to set these decisions “in concrete,” which was made. McNamara also added the critical information that there exists a tape of this meeting, in the John F. Kennedy Library in Boston, to which he had access and on which his account is based.”
And,
“There followed, on October 4, a memorandum titled “South Vietnam Actions” from General Maxwell Taylor to his fellow Joint Chiefs of Staff, Generals May, Wheeler, Shoup, and Admiral McDonald, that reads:
“The program currently in progress to train Vietnamese forces will be reviewed and accelerated as necessary to insure that all essential functions visualized to be required for the projected operational environment, to include those now performed by U.S. military units and personnel, can be assumed properly by the Vietnamese by the end of calendar year 1965. All planning will be directed towards preparing RVN forces for the withdrawal of all U.S. special assistance units and personnel by the end of calendar year 1965.”
McNamara was one of the most dishonest characters to ever serve in government so I’d want to see confirmation to back up anything he was saying. He and LBJ were kind of a matched set in that regard. McMasters “Dereliction of Duty” is a really good source for revealing the duplicity of those two using their own papers.