Yeah that is the first thing I thought.
I'm not sure if the scales are celluloid/acrylic or some other sort of rubber, but either way normally the rot shows on the blade inside the scales, not outside. Right now it was rusted everywhere except where the blade was tucked inside the scales.
Kinda sucks that I have to re-polish it, but luckily its not rusted too deeply.
i think you are right, rot is usually on the inside. It could be where you held the blade to close it, the acids from your skin have attacked the steel. This is why they use cotton gloves in museums.