Originally posted by MikeW I would view it as a "shabby chic" piece. The black, metal-bodied cameras of several years ago seem to acquire a certain cool patina when the brass is worn through the paint. Perhaps the winder can be similar. Think Willie Nelson's guitar...
Most of my 'S' bodies are in User condition - basically, so I can actually use them.
I own a Collector Grade K and Zebra 55/1.8. Neither lens nor camera has a single mark on it and I NEVER use them. Sometimes I wonder what is the point of even having them.
RE: the OP question - IMHO, anything you do that is reversible is fine. My wife collects antique American furniture. The most valuable pieces have NOT been refinished. Collectors WANT the evidence of usage over the last 300+ years and the patina of the original finish still on the piece. OTOH, careful repair or replacement of a broken part (usually a foot or drawer brass) by a restoration craftsman does not affect value so long as the original part is retained. Everyone understands all the remaining MINT AS MADE 18th C. American furniture is already in museums, so they overlook restoration repairs.