Model 12 ID

I just acquired a U.S. marked Model 12. Serial numbers match. The original barrel has been replaced with a 1946 dated 30" solid rib full choke barrel. The receiver has been electro pencil marked with US-MOD-3946. Butt stock marked on left side with what appears to be W.B. in a box with crossed canons below. My question is is it possible that the barrel was replaced by the military on 3 Sept 1946? Has anyone seen any Model 12's marked this way?

https://www.milsurps.com/images/impo...IMG_1025-1.jpg

https://www.milsurps.com/images/impo...IMG_1029-1.jpg

https://www.milsurps.com/images/impo...IMG_1027-1.jpg