I would be surprised if Mecum wrote any ad copy with respect to how a particular car may or may not be equipped.
Auction companies don't incur liability nor should they when it comes to whether or not a car is what the seller states, that is for the buyer to determine.
The problem could arise when/if the auction company is alerted to a suspected fraud and they do nothing with-in their power to correct or advise potential bidders of said potential fraud, such as add a disclaimer or to place conditions on the sale or etc, then there could possibly be grounds on which a lawyer may base their case. If however an auction company pulled a listing or even TAINTED a car which could not be disproven, then the auction company could end up being liable for seller's TIME, SHIPPING, REPUTATION, ETC.
What happens when/if someone doesn't like the fact that the car you are selling is nicer that the one they are selling and cries wolf and it ends up costing many people TONS of $$$.
Is the wolf crier liable?
Should they be?
Studying the what if's for each party involved reveals the answer is not so simple.