Window Roller for Bell Crank

Have a missing nylon roller on the front most vertical track on my 73 Swinger. I've tried themoparshop.com & looked at RT Specialties but nothing seems to be a match. The factory service manual calls it a Bell Crank. I've enclosed a shot from the manual as well as the broken piece. Would someone please help me to locate this so I can button this up? Thank you much.