I hunted the Laguna for a few years and it was taking its toll big time on my gun the first season, and cerakote helped tremendously. With that said, mine flaked on the corners and edges some of the receiver. Apparently that isn't typical and the guy who did it offered to make it right. It didn't bother me much and wasn't worth it to me to have it re-done.
I got just the barrel and receiver area done in flat black.
Taking your "field model" to saltwater isn't a good idea, but if you're gonna do it, add the protection to the metal.