Hello,
The weatherseal I'm trying to match comes from a window with an aluminum frame - vintage 1970's. There are no marking on the window frames or the existing weatherseal that I can see. It's a piece that fits on the outside and brushes up against a sliding window panel to keep the weather out. It's not a glazing piece that holds the glass in the frame. The dimensions are shown in the photos. A pretty close match is your Capitol Weatherseal Product Code:
58-177, but I wonder if you have something a little closer.
Best,
Joe