Around 2001 I was looking for a good shooter and found a Russian capture 1937 S-42 in excellent mechanical condition. It was all "matching," but a couple of the numbers had been forced. The barrel had a gross import marking on the bottom.
I sent the gun to Hugh Clark who fitted it with a new 6" barrel and made the beautiful grips you see in the pictures. Then, Hugh forwarded it to Ted Green (Thor) who refinished it. GT took a Mec-Gar magazine and fitted it with a new wood bottom to match the rest of the gun.
In the pictures the barrel appears to have flat sides, but this is just an artifact of the scanning process. I didn't have a digital camera in those days, so I scanned it on a flatbed scanner.
I fired this Luger about 20 times and put it away. Just don't shoot Lugers much any more; I prefer to shoot 22 rifles these days.