According to Lt. Goldman his platoon is part of of B-company, 3rd Battalion, 44th Infantry Regiment, "196th Light Infantry Brigade". Though the "196th LIB" historically served in Vietnam, (the men of Goldmans platoon wear the shoulder patch of the historical 196th unit), the 44th Infantry Regiment was never a part of that brigade. The 44th was formed in 1921 and was inactivated in 1947 and never took part in the Vietnam War.
The entire plot makes no sense as the Montagnards would have already had all the VC weapons they cared to collect from the VC they killed.
When Ruiz throws a grenade into the river to catch fish, you can clearly see the grenade pop back up and float on the surface just before the explosion.
When the squad and the Montagnards start cheering after defeating the VC supply train, several dead VC soldiers can be seen getting up.