My understanding it was from an elderly gentleman's estate in our county (in northern California). He apparently had over 18 Carbines, all prime contractors and some variations. I believe this is the last one from the estate.

It would be a mortal sin at least to separate the stock from the carbine. I have a feeling it came into Underwood with a bad stock, was inspected, stamped, and then put in a NOS SG stock with a Winchester recoil plate. Oh, by the way, the Handguard is a correct Type 3 four rivet, with an IO stamp.