As a suggestion, if the cover you have is pitted, instead of getting one with surface pits redone, you can buy an exact repro (shape and stampings) for around $25 from many Corvette parts places. Outside from correct fonts there are no date codes to worry about.
There are two type of repros I have seen where it comes to the 4 vent holes on the sides of the cover under the bail wire. Some have the vent punches facing out and others have it facing inside. I have only seen inside facing vents (like those shown by ko-lek-tor) and those on my 67's.
The place that has correct looking caps with the inside facing vents: http://www.westcoastcorvette.com/