Snap in glazing
A quick learner from Pennsylvania says:
October 15, 2016
I think they are norco Windows. I found some letters and numbers. IGCC CBA 3/4. Don't know if that helps. The windows are about 25 years old.
Tom from SWISCO responded:
October 18, 2016
Please see our 55-186, I think this may be a good match.