Window catch - plastic piece that screws into top of sash

I noticed one side of my window is missing the plastic piece at the top of the sash that catch the balance spring. I just purchased balance springs part# S390-29 option 2840. The window track is 1-1/4 inches wide and the sash is about 1-1/8 inches wide.

Do you sell these plastic window catches?

I was able to remove these from another window in our building that uses the same size window. There is a right and left one. I attached better pictures. Do you have available replacements?