"Surface rust" refers to a thin layer of rust that forms on the top layer of a metal object. It is usually not very deep or damaging, but it can make the surface appear discolored or rough. Full definition
There is very little surface rust, and only minor scratches. (autoclassics.com)
I think this is surface rust only and there are no holes through the structure, but I haven't looked closely yet (I'll try and take better pictures tomorrow). (mechanics.stackexchange.com)