David, welcome to the forum~!
Well, is it an original holster or one of the reproductions?
Finding a "real" test luger is an exercise... The newest information is in Jan Still's book "Central Powers", and in brief, the info states that the only true way to have (for sure) a test luger is to get one of the Bannerman numbered ones and not neccesarilly the 6100-7100 generally stated. That said, they can be found.
I don't have a Bannerman number, but own 2 of the the ones between 6100-7100... but not a holster....
Ed