Removed old transom got new one cut and ready to install. The aluminum have some ver minor pitting which I was going to skim with some JB then sand smooth. My question is should I spray a coat of primer on the inside skin prior to installing the new wood. Forgot to mention boat is a 74 Starcraft 16 ss and the new transom is made from marine plywood with titbond III for glue and 3 coats of spar on entire piece. Thanks