Interesting thread. I collect vintage Mossbergs and the US Property marked 44 and 144US are serial numbered by contract requirements. The civilian versions are not. This presents a problem with C&R log requirements. I own four M44 civilian rifles and have no idea which is which in my log. I called the ATF on this and they had no answer other than if I were to sell one just to pick one and log it out. Then there are rifles with multiple serial numbers so again I called the ATF and asked which one should I use, original manufacturer or last owner....again it was "just pick one" or "list them both". Some import number are different than any of the serial numbers. I own a Finnishicon M91 with a Russianicon SN a Finnish SN and a different import SN. I simply pick one for the log and add the other two in a remarks column just to be on the safe side. Hard to believe makers of war rifles didn't put a SN on everything. These presentation rifles weren't part of the contract requirement so essentially they are not a Milsurp? Regards, Rick.