I just accepted delivery of an Atom 2.0 w/transmitter. On the back of the wrist unit there are 4 screws, one in each corner. The top right screw seams to be covered in a grey sealant. Is this a defect i.e. missing or stripped screw? Or could it possibly be put there by the manufacturer to aid in determining if the computer has ever been opened by the wearer for warranty purposes?