Wound up with that upper and it's chrome bore barrel in the future. I do think It truly is an A1E1 from some nomenclature I noticed but not sure as I've never ever witnessed another 1. I figured this was manufactured across the time of product enhancement to the M16A2 https://coltcombatunitrailgun4578888.blogozz.com/30630511/the-basic-principles-of-colt-combat-unit-rail-gun-45