Hi James,
S/42 was a the manufacterer's code assigned to Mauser in 1934 beginning with the "K" date Luger. S/42 was used until early Spring 1939. Then was changed to 42 until February 1941. Then the code was changed to "byf" until mid-1942. "byf" is simply a letter code assigned to Mauser.
Banner Lugers were the Commercial variation produced simultaniously with the military from 1938-1942.
Ron
I must be getting old and slow... Norm beat me.
