Kitchen Cabinet Drawer Slide Mount

Looking for replacement parts for both the right and left plastic rear slide mounts. the cabinets were made by Wellborn and, according to them, the mounting assembly was made by Grass. There are no obvious markings except the 2 parts are identified with "Right" and "Left" at the top of the parts. The cabinets were installed during a house remodel that occurred in 1994. Would prefer to just replace the 2 plastic mounts and keep the original slides if possible. Otherwise a recommendation for new drawer mounting assembly would be good.