I bought this upper from a friend I get parts from for $20. He does not know anything about it except the fact he picked it up from somebody else. It is exactly like a regular A2 carry handle upper except it does not have the elevation knob. It does have a "K" stamp which is on one of the pictures. It does seem to me to be a mil-spec upper from the forward assist being like a Colt style. If anybody could help me out I would be greatly appreciative.