1) yup - wire wheel, prime, paint as desired - that’s just surface stuff.
2) I’m guessing they were installed as bare metal, and got some moisture on them. Even painted, they are going to get scratched and expose bare metal which can rust.
3) Sure, it should be caught, but also it isn’t very significant at the point you caught it, so clean, prime, paint and look for it next time.
Paul F. Dye
Editor at Large - KITPLANES Magazine
RV-8 - N188PD
RV-6 (By Marriage) - N164MS - "Mikey"
RV-3B - N13PL - "Tsamsiyu"
A&P, EAA Tech Counselor/Flight Advisor
Dayton Valley Airpark (A34)