(MamaLiberty, this one is kinda for you, given the "so what are you wearing right now?" conversation from comments a few days ago.)
I can now confirm personally that the Kahr CW40 suffers nearly nothing from a ten-minute total immersion in 40-degree seawater; one small bloom of orange surface rust just inside the muzzle came off easily 12h later with a cleaning, and shows no signs of return yet. Nor does a Safepacker "un-holster" suffer from the same fate; it launders normally and should now be salt-free once again.
The gun's owner, by contrast, was much grumpier about the whole episode, mostly because he lost his new eyeglasses, and because he held up the kayaking group, with an unexpected roll in choppy water. (Apparently he felt the need to prove his noob cred in grand style.)
Of related interest: the kayak guide was understandably worried about the possibility of hypothermia, but fortunately the Wiggy jacket performed exactly as advertised, and to my considerable satisfaction the cold simply was not an issue. I suspect he figured out that I was exhibiting absolutely no signs, and was far more irritated than scared or compromised. I wrung myself out and was back in the water in what was probably less than half an hour. (I suspect he would have been far more freaked about the contents of the Safepacker, had he been even remotely aware of them. :-)
Helluva first-kayak-trip, really. Other than the loss of the glasses and the irritation of being caught off balance by an admittedly rough-conditions day, I'd say it was all win: lessons thoroughly learned and home in one piece!