1. Although some might consider George Barnum's 11/29/1963 diary hearsay, it describes a verbal exchange with the President's personal physician Dr. Burkley which included him as an active role in the conversation.
From BEST EVIDENCE:
In his November 29, 1963 account, Coast Guardsman George Barnum wrote that as the men were having sandwhiches and coffee sometime after midnight, Admiral Burkley came in and talked to them, and said three shots had been fired, that the President had been hit by the first and third, and he described the trajectories of the two that struck:
"The first striking him in the lower neck and coming out near the throat. The second shot striking him above and to the rear of the right ear, this shot not coming out...."
2.How is Dr. Perry's original recollection of a Friday night phone call (and a second call never mentioned by Humes) to the Warren Commission hearsay? He was on the other end of the conversation. Even when being interviewed by the HSCA, he said that this was still his recollection.
3. The 11/25/1966 Baltimore Sun article which contains an interview with Dr. Boswell himself, states "The pathologists who had already been told of the probable extent of the injuries and what had been done by physicians in Dallas."; "'The wound in the throat was not immediately evident at the autopsy,' Dr. Boswell said, 'because of the tracheotomy performed in Dallas... We concluded that night that the bullet had, in fact, entered in the back of the neck, transversed the neck and exited anteriorly.'"
4. While the 1/10/1967 CBS memo by Bob Richter, reporting executive Jim Snyder's story is hearsay, it's still from the 1960's and keep in mind that people in the media generally understand that you should avoid distorting a story. Richter reported that Jim Snyder personally knew Dr. Humes, and that Dr. Humes told him an X-ray was taken during the autopsy of a probe going from the back wound to the throat wound in an irregular path. Again, Jim Snyder was describing a verbal exchange with himself on the other end of the conversation.
5. William Manchester's book The Death of a President states the following:
Joe Gawler and Joe Hagan, his chief assistant, supervised the loading of the coffin in a hearse, or, as Hagan preferred to call it, a “funeral coach.” The firm’s young cosmetician accompanied them to Bethesda. The two caskets, Oneal’s and Gawler’s, lay side by side for a while in the morgue anteroom; then Oneal’s was removed for storage and the undertakers, Irishmen, and George Thomas were admitted to the main room. The autopsy team had finished its work, a grueling, three-hour task, interrupted by the arrival of a fragment of skull which had been retrieved on Elm Street and flown east by federal agents. The nature of the two wounds and the presence of metal fragments in the President’s head had been verified; the metal from Oswald’s bullet was turned over to the FBI. Bethesda’s physicians anticipated that their findings would later be subjected to the most searching scrutiny. They had heard reports of Mac Perry’s medical briefing for the press, and to their dismay they had discovered that all evidence of what was being called an entrance wound in the throat had been removed by Perry’s tracheostomy. Unlike the physicians at Parkland, they had turned the President over and seen the smaller hole in the back of his neck. They were positive that Perry had seen an exit wound. The deleterious effects of confusion were already evident. Commander James J. Humes, Bethesda’s chief of pathology, telephoned Perry in Dallas shortly after midnight, and clinical photographs were taken to satisfy all the Texas doctors who had been in Trauma Room No. 1.
Since the book continues on to quote Joe Hagan of Gawler's funeral home, I presume that the "shortly after midnight" passage originates from him.
There, all of the evidence I posted above comes from the 1960's. Nothing fifteen or thirty years after the fact.
As Doug Horne pointed out, the original official story may have been that the throat wound was a fragment of bullet or bone from the large head shot, but then people in the investigation started realizing that the Zapruder film shows Kennedy reacting to frontal stimuli way before the large head shot at frame 313.