Steve Loeb, Ideal Music (
www.bassesonline.com) is, or was, selling some "luthier specials" No. 10 Wilfers for $3500 or 3 for $9000. These had repaired top cracks, per the ad, and, as is the case with other Ideal basses, required a good set-up. So far as I know, the NO. 10 (aka No. 500) is a mid-line Wilfer. Based on what I've seen of the current Wilfer line, this one may not be that much out of line price-wise. YOu might have a small amount of wiggle room to neggotiate.
I think what you would want to do is to take it out on a trial basis. While you have it, take it to a good independent luthier and get a second opinion. You may have to pay something for this service but it will be worthwhile to get a second look from a trained eye. If I were the seller, and a luthier, I'd be proud to show off my work to another pro.