Yes it looks like the black paint on the backstrap of the pistol has been there for a very long time, it looks like some kind of model paint. I really do not know very much about luger pistols, I read that the stock lugs were ground off commercial lugers prior to import in the 1920's. The rest of the finish on the pistol looks original to me as the color looks the same and the wear looks pretty even. I would be really interested to hear everyones opinions on my luger.
Im happy with it as I have wanted one for a very long time, I have not had chance to fire it yet but hopefully I will get time to head out to the woods next weekend, hopefully the gun actually works. I managed to order a new magazine for it from numrich gun parts.
I think eventually I would like to get another luger in 9mm to keep this one company in my safe.