I made this same reply on your other thread on this Luger:
Pretty cool pistol.
The S.C. is the Schupo of Cassel, the S.Ka. is the Schupo of Kassel(after spelling of the town name changed!).
Very neat transition on one piece. If you decide not to get it, let me know. I have another
Luger property number 113, I could start a sub-really speciality collection if I had two!