Hi HuntMaster, It would almost be as easy to find the original sideplate, as it would a correctly numbered replacement.. Here's what you have going against you... First, 1936 Mausers were rust blued, the vast majority of Mauser later production was salt blued... Second, unique font of the numbers.. I think at this point, the Mauser number stamps were a small, skinny tall font, I could be wrong on this, but at the very least the font was unique to Mauser... Third, condition, if you find any, they will most likely be beat! .. Fourth, fit, gotta fit and function, otherwise just a fancy paper weight... Now, that being said, don't give up, one of our forum members found the original correct side plate for a Krieghoff luger!!!... Infinitly more rare then a 1936 Mauser..
... But, it happens!!! And, it can happen, just maybe not in your lifetime...
... Best of luck to you, til...lat'r...GT