Mike I'm going to address this to a '50, but I think the '48 on up were the same.
There isn't any roller on the regulator. the window guides ride on the posts that are rivited to the arms and what you may think is rubber is in reality leather washers on each side of the guide. there are two different sized washers used on each post and they are lubed with lithium grease.
Take a look here, this should make it pretty clear: http://rides.webshots.com/photo/2924571610098611668SAUVbW
http://rides.webshots.com/photo/2566710950098611668bcnMYR

Denny Graham
Sandwich, IL


Denny G
Sandwich, IL