No. And most '69s have a vent tube built into the tank (if the tank is original) that exits just under the top edge of the rear bumper just left of the license plate bracket. Most reproduction tanks do not have this vent, so it is essential that the fuel cap vents properly.

You can easily check your vented cap, if you don't mind a bit of gasoline flavored air. Be sure the cap is clean and dry, let it air out for a while. If you try to pull air through the port in the inside of the cap it should flow easily. If pushing air through, it should go, but not so freely (reducing sloshing of fuel out of the tank when full).