They are only about $2.00.

If you go to www.chryslerpartsdirect.com you can order them there. Drill down on"body parts" and look at the illustrations. It is call a "Cap Back" . They do not give the part number.

I think you are better off going to your local dealer for it as this site has a minimum $7.95 shipping charge.
I can't see payng that for an item that is just a couple of bucks.