Nice Find
Paatz a relatively small firm.
Very hard to tell how their serial numbers were dedicated to various guns they made.
Impression I get is all their guns may have been one range but that certainly not definative.
The very few examples of their DSM documented and observed on the Mauser pattern are so scattered and far apart in serial range that is the only conclusion I can make looking at the other .22 models they made same time frame.
So I would be very interested in the serial number if you are OK with it.