I have a '14 Z with less than 10,000 miles. Yesterday a piece of black plastic about 3X1 1/2 in. fell of the passenger side when closing top and today the duplicate for the driver side fell from somewhere when opening the top. One side is covered in glue or some sticky substance, the other side has a white mark. Each corner has a hole as though it was attached somehow. We can't figure out where they came from, what they're for or if we should be concerned. Anyone have any ideas?