No signs, don't bother. Pretty sure it's sealed with 5200 so it may be a possibility of damaging the gelcoat or more trying to break the seal. If any water fresh or salt is entering the bracket it's probably thru the access plate(s). Having had this age bracket, mine didn't bolt across the top, just down the side, middle and across the bottom. The top would not touch the transom in some places, beware of that, so water could seep inside too.
I'd be more concerned with transom rot and the coating on the bracket with this age boat/bracket.