I’m not knowledgeable about odometers at all, but if it’s as easy as “hooking up to a computer” to get the real mileage, why don’t people do that when they buy the trucks?
Just to correct this - auctions operate with a whole lot of caveat emptor
which is why auctions are supposed to be relatively "value buys".. in an auction transaction.. if you're not sure if you're the sucker... then you're the sucker.