replacing it with a new Class C which will be delivered later this month.
All it is is an ordinary truck. The truck is bought by the coach builders who in turn make it into an RV.
1. If you 'ordered' an RV: The coach builder had to buy and/or take a truck from their inventory BEFORE they build your coach to your specification on that truck chassis.
2. If you are buying one "in stock": The coach builder has already built the coach on the truck chassis.
In EITHER case there IS a truck involved from Ford WITH A VIN.
The whole story of no warranty available sounds very fishy. And if in fact that Dealership is refusing to give you a copy of the warranty take your business elsewhere ASAP, AND report them.
Please tell us you have not signed any papers on this RV.