If they won't share the entire policy and coverage details/exceptions before you sign, of course walk away.
Delamination with no cause is an extremely rare situation. It almost always is due to water getting in - sometimes a defect in manufacturing, more often a failure with maintenance. The first can be hard to prove, the second may entail greatly increased, expensive, visits to a dealer to keep the warranty in force (far more than the manufacturer advises). They will use any failure on their mandated schedule to deny a claim. One I looked at demanded dealer maintenance every three months - with a denial to cover forever if there was even a slip of a day in the schedule. Good luck on getting dealer appointments that frequent and on time!
Spend the money on a certified RV inspector to check things out BEFORE accepting delivery of the vehicle to reassure yourself about the manufacturing defect potential. Then be rigorous about maintenance yourself (or at a dealer, but on your determined schedule to your specifications).
My out-of-warranty fifth wheel suffered a roof tear from a branch, that went unnoticed by me until a slight ripple in a sidewall was seen. The quote to repair just that and the roof, was far more than the value of the RV. With a potential of more damage discovered as the repair progressed.
My insurance company paid, since it was caused by "being struck by". But the RV was totaled. My coverage was present value, and not replacement cost. Consider that second option with your insurance, although it is many times pricier.