Mainspring replacement - not a piece of cake
 

But the new spring is in there, thanks in part to Ted, Hugh and others who posted hints (and I copied) regarding the issue. One hint though please emphasize that the Recoil Spring Lever Pin should be drifted out to free the lever so some darn fool (no name here) wouldn't spend 15 minutes trying to turn the mainspring guide 90 degrees to free it. Once that hurtle was past things progressed quickly. The trick is getting the new spring back into its proper place, after several trys with the padded vice method, I finally clamped a block of wood to my workbench, laid the Luger horizontally against it (could finally see the Mainspring guide)and guided the mainspring guide back through the opening and seating the spring guide assembly within the grip. The padded had vice blocked my vision. I noticed that the replacement spring was about 5/8's inch longer than the original, compression over 75 years must have taken it's toll. Now lets see if this thing cooks next week at the range.