PS I haven't seen the movie. But I understand that it is very good. I don't watch movies about Nam. I don't need any refresher courses. :-]
Don't sweat it. My late FIL refused to watch the (dreadful) movie "Pearl Harbor" ... he was there, didn't need any reminders. I told him he wasn't missing anything anyway, the movie sucked. I'm sort of disgusted with myself, that I wasted 2.5 hours of my life watching it. "Saving Private Ryan" busted him up pretty bad, even though he wasn't there. Too similar, I guess ... You're in good company.