A purchasing agent from MARYLAND says:
February 22, 2014
DO YOU HAVE A ROLLER THA WILL BE A DIREC REPLACEMENT TO FIT GRANT #336 SLIDERS IN 20" LENGTH"
Tom from SWISCO responded:
February 24, 2014
Could you use our 32-060? If not, please take a few pictures of your existing hardware and upload them here for us to look at.