Usually, water won't infiltrate into snugged down screws, so they won't rust if the gun is properly treated once out of salt water.
The last I heard about the "swimming" S&W revolvers, the technique was to drop the guns in a tank of fresh water, hot if possible to flush out the salt water.
After removing the guns, the water was blown out and they were lubricated with....wait for it.....WD-40.
I know, WD-40 is NOT a lubricant and it instantly causes a gun to rust and gum up.
The SEALs apparently hadn't read the message.
One of the most interesting things I ever read about WD-40 is in the book "Good To Go" by famed multiple tour Vietnam SEAL Harry Constance.
Constance wrote that when he came in from a patrol, he'd remove the plastic parts from his Stoner light machine gun and drop the assembled gun AND the linked ammo into a cut-off barrel of gasoline.
After breakfast, he'd remove the gun and ammo, disassemble and clean the gun, then liberally spray the gun AND linked ammo with WD-40 to lubricate and prevent rust.
He said he was then ready to go out again, and that in 3 tours of duty, he never had a jam from the Stoner.
True, he did this every day so the WD didn't have time to gum up, but this also puts paid to the story about WD-40 "killing" primers.
Apparently SEAL 6 and the other teams thought WD-40 was good for revolvers too.
The SEALs are super anal retentive about weapons maintenance, which is why SEALs seem to not have as many problems with weapons as other people do.
Since they spend so much time on maintenance, they find methods that work for them no matter the common knowledge that says that's not good.