:>) I repeat , I never said they did not leave the factory unmatched.
They DID leave the factory with all numbered parts matching each other.
What I did say was the 1 reciever made did not leave with the 1st bbl made on it , an so on. The parts were pulled from a stock bin , placed together to be assembled as a firearm , and at some point in the building thereof all the pieces were stamped with the serial number. This could have been a final step , or it may have been done before the parts were separated to go to other stages ( finishing , buttplate fitting , etc.) so that when they came back they could be assembled together to preserve the fitting of parts / headspacing / etc. that had already been done.

AHA--you are talking about post 15 , I was answering post 17. I don't think we really disagree on anything.
These guns were not what you would call military weapons , but rather commercial weapons pressed into military service. They were not held to the strict tolerances of other weapons because they knew the different models of shotguns from all the different factories would have no interchangeability of parts and would be just a small percentage of the weapons issued anyway. They were looking to fill a need at that time , and realized that after the war if they junked them all it would be no big expense. This would be true of all the shotguns , the revolvers , most of the .22 trainers , etc.
Chris