I'd pass too.
You have to be really careful with barrel lenses. Usually you can only justify putting them in shutter (versus buying a used one already in shutter) if they're a direct fit and you have a cheap shutter ready to go, or it's an unusually exotic or expensive lens.
Best case is above, perfect lens, good used chrome ring Copal sitting on your shelf, about $575 with nice ones ready-to-use at $750, savings of $175.
Worst case, haze, Scheideritis, and having to buy a new Copal ($450), with aperture scale (about $25 from Schneider), about $940 for 355 G-Claron with Schneideritis.
A good used black Copal 3 usually goes for around $325-350, so even with that you'd come in at around $815. And the worst case involves a lot of waiting and shipping parts around the country.
BTW, I have a 270mm G-Claron in late black Copal that is perfect but had haze in it when I got it. I shot with it and was underwhelmed. I was going to sell it or trade it, but had a box going to S.K. Grimes, so I thought what the heck, I'll have Adam clean it since I have room in the box. The difference was amazing.