DWM Police??

[Lugerdoc]

Kidvett, One possibility comes to mind re your 1918 PO8 without acceptance or test fire proofs. Perhaps your 1918 receiver was a left over part from WW1, assembled post WW1 for the police, who didn't require military or commerical proofing at the time. Then again, it may have been factory refinshed in the 1930s when the sear safety was added. Hard to tell for sure. Tom H.