I agree with Bill. This bring-back certificate does not belong with a Luger pistol.
The form and length of the serial number may give some clue to collectors of other types of military pistols just what type of pistol this certificate was intended to accompany...
How about it collectors and those who study other types of pistols... what type of German pistol has serial numbers that start with an "S' (or other alpha character) and a hyphen (-) followed by 6 numbers???
Jan C. Still? Are you listening?