Yeah Steve, mine was convert to M16A1 a one time. It started off as a M3, then convert to an M3A1, and then to a M16A1. I could be wrong, but I find it odd that they would replace the side armor and keep the top rail, so I assume that I have the original armor. It does seem that every couple of months I am discovering new things about all the holes in the top rail. It looks like mine might have even had four MGs mounted on the walls, one on each side and possibly two on the rear.