Aha, PBS gets the blame around here too, least for Pythonisms, but that day is done. The later stuff just doesn't ring true to me, or if it does, who wants to know?
Kentucky I thought was Scots-Irish territory, but I see on looking it was over 50% English; speaking of which you must have enjoyed "The Story of English" on PBS.
Alright "back to the gun" if we must.
Yes, a Mk2 is easy to spot from the cross bolt rather than the cross strap on the back of the forend.
I doubt the Pakistanis proofed anything, unless it was made at Pakistan Ordnance Factories (where all the Fazackerly machinery reportedly went)
The mixture of makers means nothing; as Peter Laidlerhas said many times, whatever parts met spec and fitted were used once in service.