1970 bolt in window questions

[1109RWHP]

What material is the best to use in between the window glass and the metal plates and brackets that bolt to it? It has some kind of rubber/tar paper looking stuff from the factory and I would like to replace it while I have everything apart.

Who makes the best replacement plastic bushings that go in the aluminum brackets that guide the window on the guide tubes? Or do all of them fit loose?