Can I program a new SKS key with an immobilizer only key?

I just went for a nice swim in the pool, and realized after 10 minutes that I had my 2004 Prius SKS fob in my pocket. Doh! Did I mention this was one of those new saltwater-disinfected pools?

As soon as I could, I dried it out and removed the CR2032 battery (wet with water, leaking corrosive fluid and clearly shorted by the saltwater). I put it in a bag of dessicant and waited for it to dry out.

The saltwater seems to have killed the SKS functionality and the lock/unlock buttons, but the immobilizer still works (inserting it into the dash starts the car). I guess the immobilizer chip is better sealed than the rest of the battery powered circuitry.

I have another spare SKS key that I had kept for emergencies only. My plan is to swap the keys: old spare SKS becomes my new primary daily use key, and the now immobilizer-only key becomes my backup.

But... from reading the programming procedures on this site, it sounds like it's not possible to program an SKS key from an immobilizer only key, because the immobilizer-only key doesn't have the SKS codes.

Correct?

So the question for me is whether it's worth buying a spare SKS key so that if I lose my now-only SKS key I won't have to pay and cajole a dealer to reprogram a new SKS key without any SKS to duplicate.

The car is 10 years old although I plan on keeping it another 5 years at least. I haven't been keeping up on all the possibilities as far as whether aftermarket or used SKS keys really can be reprogrammed; I've read people who have success and people who have had failures trying that.

 

After just drying out the saltwater didn't work, I soaked it in fresh tap water and shook it around to remove all the minerals. I inserted a fresh CR2032 battery, and now the red LED on the fob does blink when I press the buttons. But the SKS functionality (door unlock buttons and start with key in pocket) still does not work at all.

I tried the reprogramming procedure for new SKS fobs (Procedure B here):
How to Program a New Key Fob for Full SKS Functionality | PriusChat
and the working fob got it into the programming mode just fine.

But the nonworking fob didn't get acknowledged and SKS did not work on it.

I suppose my next step is to contact Luscious Garage.