I have traded into a Model 25-5 with some markings that I have not seen before. All of the markings in question appear on the left side. There is what appears to be a German proof mark on the barrel, just off of the frame. There are three markings on the frame just behind the barrel. Another mark appears just above the trigger guard.

The barrel measures 5 3/4 inches. The right side of the barrel is marked 45 Colt CTG. Serial number begins with N828.

All insight is greatly appreciated.