I have found that the pin is just for glass tilt adjustment for a tighter fit to the door frame .
I have found many of cars with them broke off the frame and window worked ok .
the cars i have had three b bodys all had them broken off and sitting at the bottom of the door and when i restore them i welded the part back on to the window vent channel run never used any type of bushing and never heard or had one rattle yett .
not saying it wont just do see it to be much of a problem to worrie about , my fuel pump is louder than most rice burners out there HA HA.