Heres a little trivia no one will care about.
Those parts are called "water shields" or "condensation shields" and I have a cousin who was born and raised in Detroit. He has worked for a couple of parts suppliers to the big boys his whole life, the last being NSK bearing. These days he is working for a company who supplies these "water shields" and a few other plastic interior pieces.
On some late model cars they are TRULY "water shields". Leave them out of the doors on a 2004 Gran Prix and you WILL have LOTS of water in the car. On many late model cars they are not just paper held in with a little spray adhesive. They are thick plastic sheets held in with butyl tape like a friggin window!
They REALLY do seal out water from the interior.