Ok, well I finally got to look at them today and meet the seller. He's a very nice and seemingly legit guy.
He's owned the yellow car for 25-years, last had it on the road in '83(when the frame broke), and started it occasionally every year, up to 5 or 6 years ago. The good news on it: All lights are intact and good condition, the car is completely assembled except for the interior, and the fact that the body is completely unbolted from(yet somehow still attached to)the frame. The bad: still has gas in both tanks, broken fiberglass on the lower fascia and general gel-coat cracking everywhere else, cracked windshield. I didn't get to see the seats, but did see the solid wood dash the seller had made to replace the original.
The black car is on a wood dolly, and the underneath looks OK. There was a rip/split on the passenger's seat, but the driver's seat looked fine(hard to tell under all the dirt though). The face of the dash looks wavy, but is still intact. Condition of the body is similar to the yellow car, and all lights are also in good shape on this one. The windshield is cracked on this one too, but he removed it in one piece(somehow). He has the head off the engine, the stuck piston removed, and a new ring & gasket set for it.
The spare frame belonged to a racer from Michigan. It's been stitch-welded along the backbone and appears solid, though it's bare steel and has surface rust.
He also kept pointing up to the attic of his garage where more parts were kept, though we did no go up for an inventory.
He did provide me with a link to a few more pictures here
At one point he hinted that $3k may buy both, but later said his wife was holding him to $4k. I think that's a bit much, given what I saw, and the fact that this car on eBay only brought $9100.
So Dr. Hess - and anyone else that's following along - am I foolish for pursuing this any further?