Provided that the work was professionally done and there is not a noticeable flaw in the interior or exterior of the camper I believe the fact that a body repair was made is a non-issue and I don't think I would even bring it up unless the dealer specifically asked. I've traded a number of campers in at multiple dealers and have never even had them look at the camper prior to agreeing to a trade in price. Personally, I would rather buy a camper that has had some body work done due to an accident but has been well taken care of and maintained than a camper with no body repair work that hasn't been taken care of ... a poorly maintained roof is a much bigger concern to me than a professional body repair.
