Aside from what resin or reinforcing fibre is used in a Corvette body, the material is painted, and thus not likely gelcoated.
For many years, the Corvette body material has been various types of SMC
, which - like any other "fiberglass" is fibres in a resin... often polyester. So yes, Corvette bodies are still mostly fiberglass, and like any other resin/fibre composite care needs to be taken with chemicals used on the surface. I wouldn't be surprised if the specific materials in a Corvette are more resistant to damage by gasoline than our gelcoat, but I don't know.