Kitchen cabinet drawer glide rear support socket/bracket

One of the drawer-glide supports which attach to the back of the kitchen cabinet broke. These brackets appear to be 2-piece -- the "anchor/backplate" portion fastened to the cabinet back, and the other which actually supported the drawer glide attached to the cabinet and fitted securely into the center slot in the back plate.

These are 32 years old, original to the house, and plastic doesn't last forever. Do you have any replacement or similar parts? Thanks!

Thank you!