I agree that "we" all would probably agree, accept, or guess that they are ok; BUT, the ATF letters and statements(I have read)-
all refer to "board" stocks.
Chances of any problem are slim, but one cannot point to chapter and verse written by the ATF that it is "OK".
Someone who has a "mauser type" stock for a luger, could go to the trouble to request a determination from the ATF Technical Division for that type stock and do us all a favor.
I personally do not have one, and don't believe they passed beyond the prototype/test stage for the military; as noted in Pistole Parabellum. The Geco ad demonstrates commercial sale of a similar "case holster", and of course they are being sold today out of Europe- where the regulations are quite different.
Shoulder stock for lugers, FN/Inglis HPs, or Broomhandles are no doubt low on any LE list; so unless one is doing something else wrong- or has 1000 guns that the neighbors find incredible- ilke the guy in California, you're probably safe! JMHO.
