Sell your kids, and buy more speakers.
Seriously though, anyone who sees the dented dust caps is going to want a discount on them. It is true that they shouldn't affect their sound, but esthetics matter a good deal as well. After looking around the web a bit, I found some pre-owed CC390's for 425. So I would say with the visible problems, you would be looking at 375-400 for them. Probably closer to 375 than 400.