"Once you put tool to the timers [by unscrewing the backplate from the block of wood and the timers from the backplate to see how badly damaged they were] it's yours. Since I never unscrewed them and looked at them, I'm not responsible for omitting any mention of the damage."

Oh no. You can't claim ignorance when you sell something because you closed your eyes very tight. Even if true, the responsibility to accurate describe damage, faults, flaws is yours. And no spin changes the fact that they timers weren't functional.

"How can you prove you didn't cause the damage so you would have an excuse to return them?"

No one who cares about Heuers would deliberately damage one. Not for money. Not for a return. Not for anything. We are stewards of these timers and watches, not vandals. This is the thought process of a mercenary, who would destroy a piece of art, of history, for personal benefit.