How thick is the back wall of a Class A? For mounting TV?

Use a studfinder to identify the stud pattern, then mount a decorative piece of stained oak plywood with routered edges with multiple screws into the studs.

Mount your tv swing arm onto the plywood. Incorporate a couple of pieces of material with Velcro fastenings on the front to hold the TV against the plywood so that it is not going anywhere when it is tied down.