Factual error: In the movie Dian touches hands with the silverback Digit. In reality Digit was a young male and not a silverback. The gorilla she touched hands with was not Digit but one called Peanuts.
Factual error: Buster Franklin's bass player is playing a MusicMan StingRay bass, even though they didn't appear on the market until 1976. The guitar isn't from the fifties either, but I can't make out what it is. (02:12:30 - 02:14:50)
Revealing mistake: The "Great Train Robbery" actually took place on a two-track railway near Cheddington - the West Coast Main Line. However, the filming took place on the Great Central Railway steam line near Loughborough, which only had one track at that time. They laid a second track for the filming, but omitted to cut down a large tree at the end of the rails, which would block the path of a train. This is blindingly obvious, especially as they show this "atmosphere shot" twice. The tree is still there the second time.