In the film, Operation ABLE ARCHER takes place in 1987...it really occurred in 1983.
When Jack is talking to the Director, you can see the Director's computer which has a 3D screen saver. This scene takes place in 1987, before computers with this type of feature was available.
During the 1975 fall of Saigon at the start of part 3, a full keyboard Commodore PET computer is clearly seen at the CIA. The PET did not appear until 1977.