If with a 16” barrel, that’s a 6520 “Government Carbine” upper. I don’t recall ever seeing a 14.5” pencil barrel on an A2 upper. A 727 upper would be A2 upper with a 14.5” M4 profile barrel. The 723 had 14.5” pencil barrel on early models with both A1 and C7, then M4 profile on C7 later on.