Re: My new M40 replica.
As best as I have been able to find, he's correct- the early barrels have the various stamps on the right (REP in an oval, upside down heart) and the other side has a date code and inspector's number stamped in it, OR it only has the "7.62 NATO" stamped on the left side (the side by the serial number on the receiver) on the replacement barrels. I'm no expert, but that's my understanding of them, anyway.