Henry's 70 Dart Swinger

does anyone know if they make plugs for the a/c ports coming out of the firewall. i was just going to make my own out of a couple of nuts with some metal welded on the end and painted black. this would plug the holes off and still be removable for the future if i ever put a/c back on the car. but i thought maybe someoone has plugged these before and knows a better way.