Tony,

Here is the cab manual that should help you see how to replace them.
https://www.flickr.com/photos/advance-design_parts_co/sets/72157641244124604/
Also here is an interior door (47-50) shot of all the bits together.
https://www.flickr.com/photos/advance-design_parts_co/14184302391/in/set-72157631868452754