JFK is a film that sets out to explain one man's quest to find out the truth over the assassination of the former president John F. Kennedy. While Glory is a film about an all black regiment in the Civil war being lead by Col.Robert Shaw. These two films may seem unrelated but in actuality they are a bit more connected than most realize. While JFK itself is a bit of an interesting movie because most of Jim Garrison's claims have and might not ever be proven.
JFK and Glory are two films that in regards to the production of the film itself are similar due to the fact that while both based on a written work, JFK being based on a novel by Jim Garrison along with another by Jim Mars and Glory being based upon the letters of Shaw. They both are criticized as well by historians glory is more of a historical fiction movie with real people but some characters are still made up along with certain scenes the filmmakers decided to throw in that never happened. JFK is similar in that certain scenes are made up for the film such as Jim Garrison's big speech at the end while it was a mix match of different speeches he had told over the course of his long crusade he never said that entire speech in court. The two films are more Hollywood than historical but for the most part stay true to the historical side of things.
JFK itself is a bit of a hard movie to correctly say if it is historical accurate or not due to the fact that Jim Garrison's argument was according to the New York Times dismissed by public officials and experts but at the same time The Warren Commission's also was full of inaccuracy's itself. So while the film being based upon real people according to Wikipedia and IMDB every major person in the film is real. While two people having slight changes to them one being the gay prisoner "Willie O'keefe" who was not a real person but based on 4 testimonials from 4 different people (Perry Russo, David Logan, Raymond Broshears and William morris.). The other character having an even smaller change and that being their name, Jack Martin the old man at the racetrack's real name was Edward Suggs but he went by Jack Martin. Every other major character is based upon a real person and the cast looks strikingly similar to the person they are portraying.
Personally I would have to say for now that the movie is split down the middle in terms of it's historical accuracy due to the fact that most of this info is classified and won't be released any time soon regarding the JFK assassination. Even reading primary and secondary sources there is a confusing grey area that they find themselves in. On Archives.org reading the house committee of assassinations report from the 1970's is still a bit confusing due to the fact they state that the CIA, FBI, Secret service, Cuban Government, and Soviet Government were not involved with the assassination but at the same time saying the secret service did not provide adequate protection for Kennedy and that the Department of justice did not do a good job with leading the Warren Commission's investigation of the assassination in 1964. This is further jumbled that in the film and reported upon by the New York Times that this is basically Garrison's whole argument that the anti-Castro extremists in the CIA were in on the plan to kill JFK. The Reasons being that they did not want Kennedy to ease tensions with Russia or Cuba along with retreating troops out of Vietnam. In the movie this point is also shown by the character Mr.X who is based on L.Fletcher Prouty a man who worked for Kennedy in the 1960's but the problem with him is that some of the claims in the movie have been debunked by archive.org and other websites as well.
Even Lee Harvey Oswald himself is in a confusing grey area, on PBS.org in an interview with his brother Robert he states that Lee acted to kill the president alone because it was a result of all his past failures, and plans yet he also says his brother was pretty smart for the marines, and even after leaving marines he got accepted into a school in Switzerland. Doesn't really seem like that much of a failure to me. An article written by Paul Gregory for the New York Times again disproves Robert's Claim of the failures by stating that Oswald was a bit of a local celebrity in Russia but then states when he came back to the US he was very jealous, controlling of his wife, refused to let her learn English. So even people that knew Oswald can't decide if he was really a nutcase acting on his own due to failures in his life or a guy who was set up by others.