I'm not to confident in the single fiberglass spring holding the truck up expecily if I haul anything.
The empty weight of a C4 Corvette and an AD 1/2-ton are very close to the same so empty I'd have no concerns about that fiberglass spring.
But you are right, the GVWR (LOL!) of the Corvette is nearly nothing more. Basically a couple of passengers and a little hand luggage will have the car touching bottom in my driveway.
An additional reason to consider alternate springing is that the fiberglass springs are really very stiff designed to create extremely good handling. Depending on the year and model your ride may be very harsh. The earliest ones are the worst.