Greetings All, Hopefully someone will be able to help me! I have been looking (on and off) for months for the name, a part number or somewhere i can get this part. It is located on the Drivers door, its a guide that the window will go up and down on, the "rubber|felt" fell out and its not staying in, causing extreme play in the window left and right. 1972 Riviera, I apologize if I left out any important information.
That felt is not meant to go into the plastic guide. There are likely several factors at play which is causing slop in your window. Rollers and tracks, etc...also keep in mind that your door panel will take up some of that slop when it is installed.
So I did eventually muster up enough brain power to look at the fisher body manual I have. Its called a lower sash guide, per all of the pictures and diagrams I looked at there is no felt above or below the sash so either it is inside the sash itself or someone put it there. "Tinkering" around in the door, when I crammed the felt in the guide, all the play virtually went away. So that is why was leaning towards it needing to be in there. Still no luck trying to locate a replacement online.