Drawer Glide Mounts?

I have a circa 1960s Broyhill high boy with two top drawers each with bottom center drawer glides with a one inch wide rail and are 13 3/8 inches long. The rails inside the dresser are squared and don't have any indentations or grooves along the side lengths. The drawers slide easily but when pulled out they fall down since they aren't attached in any way to the glides?they just rest in the track. Seems like there is a mount or something missing?? Appreciate any assistance resolving what is needed to make the drawers slide out without dropping down. Thank you!