My buddy got a 270 for almost free a few years ago. A previous owner put the gun in a cased & left it there while it was wet, the gun was rather funky looking. It did get a new rebluing, but never looked great again.
If I had a gun that was totally wet I would error on the side of proper care, including under the barreled action & take it off the stock. That may not be something a 'bench-rest' shooter would do before a match, but I'd take the minor risk. The few times I have done it I haven't had any problems with notable changes in zero. Truth be known, most of my shooting is 40-75 yards anyway.
Back in the 90's I was going to take a young shooter out with his fairly new 22 rifle, single Mom household. I started by asking him to show me his rifle. He presented a newer rifle with a fair spattering of surface rust. The very 1st thing we did was go over proper gun care. I made sure he had the essentials of gun care. Hopefully some of that stuck with him.