I bought a GW690 (1) on Ebay for a good price. It had a new shutter installed about 2 years before I bought it, a low count since then, and it has worked very well.
If the rangefinder works well, etc., I would first run some test rolls through it. One roll, sent repeatedly to test the wind mechanism to make certain it is solid and consistent. If this checks out, send it in for repair. The worst that happens is that KEH sends it back unfixed. You then send it back for a refund. Second worst, they can't fix it and you get a refund. Third worst, they fix it and you have a nice camera with a recent overhaul. None of these 'worsts' sounds bad to me.
But do some shooting and testing in the next couple of days just make certain that you want the GW690. This particular one or another one, it is not for everyone (which can be said for all cameras, eh?).