No Jetfire convertibles were ever built. The dealer could have made one up to get a sale, but unlikely. It could only be validated by factory paperwork, like a Protecto Plate. Someone built this car, its been done before. And its been customized.
Value would be what a custom 62 convertible would be worth, what the condition is, plus the value of the turbo, and all the Jetfire trim. $10K?