I've yet to check it today, but I finally got clean patches yesterday. I'll check it again today and again in a few more days.
I was just concerned that maybe I had more than surface rust, and wasn't sure what I'd do about it or how to know the difference.
I'm chalking this up to a lesson learned. No matter what clean it ASAP! If you won't have the time to clean it that day don't shoot it!