In May we traded in our 2007 Jayco Eagle 322FKS sight unseen, by the dealer. They gave us a trade in price and that was that. There maybe some fine print in the contract that allows renegotiating if there is "major" damage to the trailer upon final inspection????
And yes we inspected our roof frequently for cracks - cuts etc....That's the weak point- if the roof leaks you're looking at major repair work should the trailer rot- delaminate etc...
At least the OP was honest and faced up to the situation.
Good luck on the new purchase.