As I said, I had no idea what you were building or who you are.
9\10 threads about cams, the op has no idea.
The fact that you came asking about something as simple as surface rust lead me to believe that you may have been a rookie that was looking at some cheap cams from jimmy around the corner.
Put it all together and it looks as it looks. I was trying to help out a potential rookie.
But, you came out with your chest puffed out and lots of dickhead attitude instead of correcting me.
Anyway, good luck with your surface rust.