Replacement window guides

I am looking for replacement parts for my windows. I believe that they are window guides/spacers. I am attaching a photo for better understanding. They are the pieces that clip to the window assembly itself and spaces that within the sash. It looks like there are (4) per window assembly. I purchased the top sash guides (part#18-166 Kinco) last year. Any help with these parts would greatly be appreciated.

Thanks, Lee


As you can see on the second picture, the part is missing which causes the window to shift.