Old monarch safety mirror, roller door upper guides broken

I am trying to replace these upper guides (see photos) for my sliding mirror doors. The doors are on bottom rollers and these "y-shaped" forks are keeping the doors aligned by clicking around the upper track for the door. The upper track that is installed is meant for more standard hanging rollers. These upper guides work by using a plastic tab to click onto the hook of the track and keep the door aligned. All of the plastic tabs have broken off and need to be replaced. On doing some research, it seems those parts have been discontinued and I need to find the current replacement (potentially a spring loaded hanging roller or just regular hanging roller?
 
The dimensions of the current bracket is 2.25 inches wide (at the metal bracket base) and 1.5 inches wide and the top (plastic y forks). Depth of the y fork is 1.25 inches total and .6 inches dee for the groove
The metal bracket says ACME 3750337.
 
Any help identifying the right replacement part would be greatly appreciated! Thank you!