The fake stamps started before the WW2 rifles and carbines surfaced to collectors and shooters. now even Gun Parts (Numrich) sell poorly
made stamps for the new collector/shooter.
I have a friend that goes to the Reno NV gun show, and there a vender who has a table set up just to
stamp your carbine or rifle cartouche at his table. This way you save shipping, just bring your stocks
and have them stamped right at the show.