The rubber piece is I think 1076860180. 25.88 here.
http://www.trademotion.com/partlocator/index.cfm?siteid=214660&catalogid=0


Did you install the wide chrome piece from an earlier model?
If so you will also need the crome rails 1076860336 & 046. 45.00 each. You might verify the PN's are what you are looking for before ordering.