Robert Richardson had said that the warm tone for some scenes in "Platoon" were done in printing so I suspect the same thing happened in this movie for day exterior work.
There is a February 1980 article on "Born on the Fourth of July" -- in terms of the warmth in the Vietnam scenes, he doesn't mention any filtering. It does say that in the second Vietnam sequence, there is a harsh yellow tone "some of which was achieved in timing" -- which implies some of it wasn't, so maybe that means some filtering.
He did mention in the AC article that one night scene on a college campus was shot on 250D 5297 stock so that the background tungsten lighting would render very warm -- foreground faces were lit with daylight units.
The article says that the stocks were 125T 5247, 250D 5297, and 500T 5295, all rated slower. One late shot in production used the new EXR 50D stock. Another magazine (maybe ICG) mentioned something that the AC article doesn't, which is that the opening childhood scenes and parade were shot on Fuji 64D stock, along with smoke, floating pollen, etc. (much of the scene though is a dupe because there are titles running through it so it's hard to judge the stock.) Though this movie was made before Richardson got into ProMist filters, the opening scene to me has some halation from a filter, looks almost like a Double Fog or LowCon.