Found these on a custom home in Kaneohe Hawaii built in 1988. Cannot locate the drawer slider track rear plastic holder bracket on Oahu so far, City Mill (Kaneohe), Home Depot (Iwalei) or Lowe's (Iwalei).
Tenant threw out right bracket. Brackets are cracking and falling apart and need to identify and find replacements for several drawers (8 pairs).
Maybe the barcode label will help you.
Richard