did any of the 63 corvettes have open vent on the side of the fenders

Hi pgrubb! I'm not exactly sure what you are referring to here but here's a link to a great source of information about your classic Vette, starting with a gallery of photos to see if you can see what you are looking for.

Grand Sport only, if I understand what you are asking.

You may have a car that had side exhausts at one time, and the holes were cut to allow the exhaust pipes to exit the engine compartment.