In my opinion, if the engine and gearbox have been removed, the only thing which might have survived capable of being used is the chassis, and some suspension and steering parts.
With the heat generated from a fibreglass fire, all rubber would have been affected, solder in the radiator would have melted, only steel would have been unaffected, and that is the chassis and suspension.
4 wheels possibly may be re-useable, but the cost of moving it anywhere and stripping it, and disposing of the rest outweighs the value of the salvage.