Having been to one or two Mecum/BJ auctions 🤣 I'll just state the obvious. Sometimes the pictures or shown on TV hide flaws (besides things that have been mentioned). Last "fresh restoration" Monte I saw already had rust bubbling up under the new paint. You or someone you trust has to lay hands/eyes on the car.
And unless I missed it, the auction doesn't specify its an SS , ( which I would assume would attract more buyers) so maybe the seller hasn't provided the build sheet or supporting documentation.