luger holster

I bought a brown holster with these letters on belt holder were these letters T.D.L. 28, P.Plendo, Straubing. One the inside were some proofmarks that can't be distingued but the letters 37 and Bennes D. Will some expert please help me with this. Also someone named Capt. Kisser had scratched their name .It also has brass swlives for shoulder straps