My buddy has a 07 cobalt that he is putting zzp valve springs in. well when taking the cams out to get to the springs, the guy helping him (NOT ME) took the sprockets off the cams, and didnt mark them as to how they needed to line back up on the cam. Now going by what I saw last night, the sprocket can bolt to the cam in one of 2 ways. In my head, this tells me that one way will be right and the other will be 180* off. How do we find out which way is right and which way is 180* off? Are they marked and we are just missing it?

Only go on one way. They can not be installed 180* out