I was in the Louisiana National Guard for 13 years, did one tour (1 year) in Iraq/Kuwait early on. I had always carried an M16 til that deployment, when they asked for a volunteer for a SAW, I bout tackled them for it LOL. None of my section (I was in maintenance platoon, transportation company) could understand why I would take on the extra weight...til we got in theater and started running missions BEFORE our crew served weapons (M2's) arrived on the boats, then whomever was tasked with following the convoy as maintenance support was waking me up and asking to borrow it! Course I gave them grief, but it WAS the best firepower available at the time. As far as serial #'s, I MIGHT could come up with it if I really dredged the old memory, but probably not. But as stated above, thankfully I never had occasion to fire it other than test firing, so maybe that's part of it? Plus I only had it assigned for around 13 months or so, probably would know it still if I had packed it the whole 13 years