I myself would clean/prep (and prime of you could) the area and would use LifeCaulk by BoatLife. It is as tenatious an adhesive/sealant as 3M 5200, but the tubes last 2-3X longer and tend to harden in the tubes like 5200 does.
Note I will readily admit that 5200 is easier to find, as even Walmart now sells it under their own name, look for "polyurethane adhesive" in the boating aisle.