[Ron Wood]

"Stark" is German for "strong". The marking on your magazine could be anything from a former owner's name to an indication that a stronger magazine spring was installed, or something else entirely.

The left grip on your Luger was cut for a magazine safety but there is no positive indication that one was ever installed. There is no visible cut in the side of the frame for the end of the magazine safety spring, but there is some discoloration in the photo of your Luger that might indicate a welded up and refinished cut. The glare on the photo makes it difficult to tell for certain. If you remove the side plate, is there a hole in the frame as shown in the photo Pete posted? That would indicate whether a mag safety was ever installed.

It is easy to see in your photos that the gun does have the sear safety.

One thing that would help improve the ability to clearly see the markings in your closeup photos would be to reduce the glare from the lighting or flash. Clear closeup photos are best taken in natural light, such as outside on a partially cloudy day or in a well lighted room so that you do not have to rely on harsh lighting to make the photo. It took me a while to learn this trick (and I still don't always get the photo I would like).