I bought a new to me TT that is in really great shape and had very few areas of de-lamination. I noticed that the dealer the folks I bought it from who they got the unit from a year ago, went over it ...
The Sealtech Leak Test can be done on pretty much any RV... Regardless of what kind of siding it my have. They all tend to leak after time ! I would recommend getting your RV tested once a year if you are driving it around... Just as a preventive measure...New leaks can open up at any time.