Undoubtedly there is some amount of rare and desirable parts in there. However, a) $1,500,000 is a lot of money, particularly for a load of obviously well used/tired parts and old cars, and b) organizing and moving the stuff will be a very difficult task.
I wouldn't think this stuff would go for more than a couple hundred thousand dollars as a single sale. If the stuff came with an operating/functioning business with some goodwill/reputation and a decent facility then $1M+ might be acceptable to some buyer. As-is however I doubt the seller will get anywhere near the starting bid.