So, my luger spent a couple days with Lugerdoc. After inspecting it (we found the hold open is not a matching no.), he put together a breech assembly with firing pin and extractor that'll let me shoot the thing without fear of breaking the original numbered parts.
So I took it out this evening and put about 50 rounds through it. Other than one misfeed (I blame my reloads), it functioned wonderfully. Loving this gun.