The rocker arm assemblies will fit on either head. There is no actual left or right. I'm not familiar with Comp Cam's rocker arms, but it is likely the rockers will have to be shimmed, so the roller tip is centered on the valve stem. This is more important than the pushrod being centered in the bore. You will still have to check for clearance in the pushrod bore. Sometimes they will rub. Here's instructions from Comp Cams
http://www.compcams.com/Instructions/Files/128.pdf