hiya Mike,
Key word: DRY mounting.
Forming gaskets in place, like on near vertical surfaces, must be an artform in and of itself. I will never be able to do it. But if you are squeezing dry silicone rubber between two immovable objects, it's a gasket. Probably has an effective working life of 50 years, longer than you or me for sure and five times longer than 5200.

Ever hear if those plates are still waterproof?