The watch is perfect as is IMHO. I would not change a thing if it were mine. The patina is a "badge of respect" from the age and use of the watch and is consistent with the overall piece. If you were going to do anything, find a NOS or doner bezel & insert. But, keep the original as is. The majority of buyers that could afford this piece would prefer it as it is today and it will command the most that way as well. Hope you don't mind my offering my opinion. Take care.