Surplus part number match
 

Gun is military 9MM Luger with date of 1915. I remember seeing an ad or web site were they would look at their parts to see if they had any whose numbers matched your numbers. In other word, if you needed a replacement extractor, which I do, they looked for one stamped 61, which is what I need to match my gun. My gun is not 100% matching. The locking bolt is marked 64. Does any one know this company or individual? If I could find the replacement extractor and the locking bolt, I would get both to make it a matching numbers gun.

It would NOT be a matching gun.
The parts were numbered because some fitting would take place during assembly and the fitted parts would be numbered to the gun.
The numbers started again with every 10,000 and every year.
You may get numbers to match but they are not fitted to that gun - you would be faking a matching gun and it may not function correctly.

Most small parts require no fitting and will drop right in.
I don't expect much problems with a takedown lever.

Side plates, firing pins and sears are a bit more tricky and even dangerous in some cases.

To be clear, if I found a surplus part bearing the same number, 61, as mine, if/when I sold the gun, I would let the buyer know. Just like if I have to buy a repo part, I will keep the broke extractor.

Again, my question is if anyone knows of some company or individual which offers this service.

I know of no company.
If you put a WTB ad in the appropriate place on this forum, someone may have have
the # you're looking for.

Didn't Lugerman have such a service?

I think he has a renumbering service along with refurbishment.

Thanks everyone for the info. I have decided to just get a reproduction extractor and go with it. Again thanks.