Looking for replacement window plunger pin retainers

Hi, please see the attached photo. I need additional plastic window plunger pin retainers for my Marvin windows as shown. I have the correct window screens, but I am just missing the little plastic retainers that need to be pushed into the actual window frame. This way, the plunger pins on my existing window screens will have something to "plunge" into to secure the window screen to the window frame.

The actual plunger pins themselves are about 7/10" or 8/10" wide. I'm not sure if that makes a difference or not.

I appreciate your help!