Need a plastic part for a drawer glide from a Vaughn of Virginia furniture piece.

We purchased this Vaughn of Virginia armoire in 2001. The plastic part broke off so now the drawer won't stay on the track and the drawer falls out when the drawer is opened. I just need the brown plastic piece I believe to keep it on track. I included a picture from a drawer where the brown plastic piece is intact. Please let me know if you have any of these parts or where I could find one.

Thanks a bunch!
Lisa