Huvius,
While there is some corrosion on the extractor, I don't believe the grooves in it are caused from wear. Those were designed into the guns' extractor to help push back the firing pins on opening the gun. I suspect the corrosion was caused by corrosive primer fowling mixing with moisture and lack of proper cleaning after firing the gun. The old time primers were very corrosive indeed. Add in a little water and you have acid. I also don't think this was refinished. I would say that all those pretty colors are original, but with todays craftsmanship by a few professionals, it is very hard to tell, in some cases. All in all, it is a very nice gun, one I would be proud to own! Bob H.