Another request on markings...
 

I have a 1918 DWM in 9MM with the standard 4" barrel. The pistol has a device on the side of the action that may be this "sear safety" I have read mentioned? Does this indicate it was issued to a civilian police department?

Anyway, it has SVI 1440 stamped on the front of the grip frame and I was hoping someone could explain its meaning to me. Thank you very much.

The sear safety bar is on the left side of the gun as it points away from you, just below the toggle. It has an elongated semi "Z" shaped bar with a small pin on each end that holds it in place. This prevents the sear from being released by pressure from the side, as Thor has repeatedly stated, a disassembled luger can be fired if a round is in the chamber with the bolt & toggle locked by pressure on the side. The sear safety prevents this, and it was on Police models. I took the sear bar out of mine and put it up so it couldn't be lost while firing. It would be difficult to replace and is not necessary to operate the gun. The safety still works. Sorry, I can't help with the markings, and welcome to the forum.

RK