Nylon window bushing

[MTPOCKET]

Need help in locating this part in the picture below. It is the white nylon bushing for the regulator to the window frame.I have two that are at the top of the frame and one that is inserted into the frame. Any help would be great appreciated. Thank You.

[Roth68rt]

Year One has a B body window roller kit, has everything you need.  Just rebuilt both rear mechanisms and used everthing in the kit.  Found it was easier to reuse the old locks though, the new ones were really stiff.  Also had to shim one of the rollers, kit isn't perfect but very useful and worth the price IMO. 
Steve

[resq302]

I think they kits are available through either R/T Specialties or Charger specialties when I got mine.