So I was watching a documentary abot the Vietnam war when I noticed this, and thought it looked a lot like one of the patches on the pre-pro 1 and 2 gloves. The colors are always a bit off on those pictures making it hard to color-match it, and it could of course be dyed - but it's very similar I think in both symbol and size.
Look at His shoulder patch here:
compared to the best picture i could find:
i tried searching a bit to see if there was anything I had missed and maybe this was common knowledge but I found no such thing.
This is the source of the documentary btw:http://www.youtube.com/watch?v=x9jpgLRuf3o