Window frame part

These window frames have a small metal piece that engages the window when it is fully raised, so it can be removed from the window frame. One of the pieces broke. The photographs show part of the piece still in the window frame and the part that broke on a table. The third photograph shows the intact piece on the other side of the frame. I recently bought replacement channel balances (see below). Do you sell replacements for this part as well?
29" Series 395 Channel Balance
S395-29
Option: 2860
Quantity: 4