Drawer Guide for Custom Cabinet

My first "functional print". My house was built in 1959 and the cabinets were custom made. The drawer rails were made of wood and had a piece of plastic to keep the drawer on track. Needless to say I had a hard time finding a source for the parts. The piece on the left is one of the originals. Time has not been kind. The middle one was the first draft to see if I got the measurements right, and the one on the right is a "final" piece.