[Thor]

Can you tell if it was removed or made that way? If it was made that way, the bottom of the grip strap would have the same curve side to side as the top. If it was removed, then it would have a flatter spot at the bottom. Serial number of the frame and suffix (if any) MIGHT help also. It appears Erfurt started the numbering sequence over each year, but the later years had more production. This number is located on the frame just above the trigger guard when viewed from the front (make sure the gun is empty and safe first) Generally Erfurts made from 1911 to 1913 did NOT have stock lugs and those after 1913 DID. It appears that those issued in 1913 can be found with and also without the lug. Erfurt stopped production in 1918 (End of WWI)