with the 2nd model Russian the parts were serial numbered to the serial number on the gun in place of where the Assembly Numbers were on the 1st model Russian.

at factory level, when cut for a stock, the serial number would have been placed a bit further back with smaller stamps, perpendicular to the original set of numbers ... or where the original set of numbers should have been had it not been cut for a stock.

However, when the distributor, dealer or arsenal added the cuts for the stock, they likely would not have restamped the serial number as the factory did.

A few pictures would be extremely helpful.

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ANTIQUESMITHS
LM1300 SWHF425