I recently purchased a set of comp 1621-16 ultra pro magnum rocker arms, and I have a question about the bushings that are installed in the rockers. While inspecting them, the bushings appear to be covered in some sort of paper material that is peeling off in spots on some of the rockers. I'm assuming that this material gets removed before installation? If so, how do I do it without damaging the bushing because it does not come off easily. There is no mention of this in the instructions.