Hi Chris,
Yep, humidity and showroom finishes on models don't go together, that's for sure, as many old model bodies in a box in my attic attest!
You can try something, although it will be difficult since all the small chrome and detail parts are affixed, but you can get some #0000 Steel Wool and carefully rub the "Orange Peel" off.... being careful not to rub through the paint..... then mask off the interior and windshield, and spray a coat of Gloss Coat over the car (in an air conditioned inviorment)
It'll be tricky, but it's the only solution I can come up with. I love those old Corvettes, however, and it's always good to see one being built! You done a great job!
Frank