Gerben,
Thank you for your comments. Your observation on your S/42 is well taken and is one of the many additional variations that can be found among the different manufacturers. The different shaped transitions from the trigger guard to the front grip strap, the Mauser "hump", the variations in machining the groove in the stock lug - the list goes on and on. I will let that essay to another student of the Luger (mostly because I don't have examples of these "reproduction"
Lugers to photograph!).