The snap in glazing appears to be Capitol Snap-in code 55-006-6.
I really cant find the exact Top sash, the 18-009 is close but it doesn't look like the screw holes are spaced far enough apart. Nor is it as long (1-5/8") as mine.
If there is room to drill another hole, I could make it work but had hoped to get the exact replacement (or as close as possible).

