1985 All Weather Window

Please help me to identify this small gray part on my All Weather aluminum single hung windows. There are 2 on each side of the window, one lower and one higher, 4 total per window. Where these parts are missing, the window does not sit squarely in the frame and does not open easily. I appreciate your help.
Janet

In reading past discussions, I see that the part is called a face guide. This is a picture of the part. The dimensions are 1/2"wide x 5/8"for the long side and 3/8" for the shorter side. Do you have anything like this?