I asked the seller whether the coin was actually bent?
He replied: "There is a wave in the planchet"
This is a seller that turns over hundreds, if not thousands, of coins on eBay every year ... most of them quite good, actually (I've bought from him before). I hope sincerely that he is not slipping. At least it appears that he is honest, although the right thing to do in an auction like this would be to call attention to the defect (IMHO).
After all, when I get a coin like this by mistake, I just take it to the bank and take whatever they offer for it ... especially for common dates like this.