Shit, look at Oliver Stone's great but incredibly incorrect JFK.
Where did you hear it was incorrect? B/c Peter Jennings (Rip) can kiss my arse!
EDIT-(MAYBE...Jim Garrett was a carpet bagger. But come on...he was the first to question the obvious technicalities of ..."Back and .....to the left...." Plus, the movie opened up many a mind to the possibilities of an OBVIOUS conspiracy who otherwise would have been in the dark.)