My feeling is that yes, you likely need to have this replaced. Mold is nasty and dangerous. Try selling a house that's had a mold problem. Re the manufacturer, depends on your warranty, but that is more of a caulking maintenance issue rather than a part failure. If you are a DIY type, if it's not a very large area, I'd be inclined to see if the manufacturer has the same wallcovering available and make the cut in that area yourself. If it turns out to be more than you bargained for, it'll be a dealer thing. If you DIY, remember the gloves and mask. You can get mold treatment products at Lowe's or HD. Then remember to reseal the whole thing and check the rest of the camper. Good luck.