That is delamination on the passenger side under the bunk window. A leak there can mean rotted substructure under the window and in the floor of the bunk area. Very expensive to repair and it may never be like new again.
At over $19000 asking price you may be able to do better.
There are many guys on here that have undertaken repair projects like this and some did a good job. If you have experience in this type of repair it might be a good project vehicle if the price was about 1/2 of current asking.
Owning an RV is about getting out with family and friends and having fun. A $10,000 RV with ugly carpet might hurt the eyes but if it is solid and mechanically sound it might be just the ticket.
A friend of mine had the ugliest two tone green class C you could imagine. He and his family had so much fun in that thing, years later they still laugh about it. For them ugly was part of the fun.
By the way, what you heard about delamination is true, unless you are a super handy guy, avoid it at all costs! I would take old, ugly but in good condition all day long over newer with delam!