The seller totally changed his tune and issued me a full refund. A huge surprise. I didn't ask for this, he just did it. It's too much, actually. I would have been happy with a little beer money. The packing was excellent, and the box was not damaged, so the problem was preexisting. Maybe he was feeling guilty?
Anyway, I'll dress the spindle side and cut the face to fit my chuck. I should be able to skim off at least some of the dent on the OD, because the plate is a little larger than my chuck.