In france a repainted black M3 is more like 1300 euros and can take a long time to be done for example by Lutton in England. I choosed to buy a spare M4p brass top plate that was not painted showing already the brass. Then I just switched both top plates. And yes I have worn the black paint on purpose as it is so nice to be able to use a worn black paint M everyday without being a millionnaire, it is also a popular fashion amongst japanese leica photographer (I met a japanese M6 user in Vietnam a couple of years ago and he had what I would call the most worn M6 I ever saw anywhere! (it was almost white silver all shiny, kind of weird if you ask me, the black paint showing brass is a lot more sexy imho