Tim,
Your Luger is an East German rework of a 1917 Erfurt. It has a replaced barrel and the toggle train from a DWM Luger. The grips are VOPO, or East German Volks Polizei. The bolt is defective and will not hold the firing pin spring retainer. Check with forum member Lugerdoc (Tom Heller), I am sure he can provide you with a suitable replacement.
Whoops, too slow...John aced me out!