HouseApe - thanks for catching that warranty note; we're a few months past the expiration, but it can't hurt to ask. That information came from the manufacturer, but it's obviously conflicting with the book.
Carpetguy2 - that's not great news, especially since mine's NOT under warranty. Not sure how eager they will be to replace the sidewall on a camper six mints out of warranty, owned by a second owner, at their expense.
Wagonqueen - I really don't know, but am getting out checked out. The wall doesn't sound hollow, there's no sign of any leak, and so on.