I'm a complete amateur ,and managed to pull it off, so replacing the binding itself isnt that difficult. If the body has to be repainted and the binding scraped, that is a good bit of extra work, though $500 seems high Minus refinish. Id shop around a little, but don't expect this to be cheap. I have great admiration for people who do this kind of restoration for what works out to minimum wage or less. You had the same sticker shock I did on the Winfield binding, but with only two known sources for the correct material, they can charge what the market will bear. I'd post on Ricresource, some incredibly good Ric restoration luthiers and refinishers on tap over there. Good luck with it, hope you bring that old bird back to its Glory Days.