Bingo!
Does the damage matter from a safety or risk standpoint? In this case probably not one bit. But it does matter to the fickle buyers that are out there and last I checked, we were still in a buyers market.
So the real question is....how bad do you want this airplane? Is this the airplane you really want, or are you just trying to get the best deal on that model? If it is the one you want - then offer a price the seller will take. If you are trying to get the best deal, discount the price to what you think it is worth and if the seller doesn't like it, you move on to another airplane. That airplane may or may not still be there in a month or two.
If there were 5 comparable models available and aside from the damage history, I'd make a low offer on this one and see if the seller takes it. If this were one of two available and aside from the damage history, this one was a better plane than the other, I wouldn't even consider discounting the price.