On the iPhone 4S Mirrored Rear Panel there was a clear plastic covering on the INSIDE side of the Panel that covers a jagged black area. There is also a small plastic covering over the camera lens, also on the inside side of the Panel. The iFixIt step-by-step instructions do not include any information about whether to remove these or leave them. I chose to peel them off and it appears everything works okay. But there probably should have been a mention about what to do with these "stickers."