he said "the rubber piece in the SLOT,..."
Thanks deQ, got it.
The rubber piece actually wraps around both sides of the glass under the mounting bracket and is U shaped, it is still available, item 5 here:
http://www.penskeparts.com/DiagramsMain.aspx?vid=47811&rnd=03192010
Edit: Link doesn't seem to work, go to 51/38a, part 51367740107, $72.