Already responded to by "THE" authority on the subject.
https://www.saacforum.com/index.php?topic=14729.0
[quote author=Cobra Ned link=topic=14729.msg167033#msg167033 date=1674594366]
To clarify, CSX 3063 sold for a hammer price of $600k plus an extra $60k in the form of the "buyer's premium" (read that as Mecum commission, which they collect from both the buyer and the seller). And most certainly, building a "1965 427 Competition Cobra" from a chassis that was 6" longer than a Cobra chassis and was built as a prototype as a different car altogether, then modifying it 25-30 years after the fact into a "Cobra" has a definite effect upon the sales price. I would submit that Marilyn Monroe in a blue dress may indeed by the same a Marilyn Monroe in a red dress, but a cousin in a satin dress some 25 years later is something else altogether.
[/quote]
Posting it here will get you the same response, which is why I quoted it here, and linked to the original discussion, as is required when doing so.
Bill S.