When I bought my kit in '89 they asked if I wanted the roll-up $895 window "option". It was not available purchased separately - you bought as a different kit. It has a taller "D" windshield so taller top. It been reported that the window and windup assembly was from a Chevy Chevette. Over years I've only seen maybe 4-5 CMCs with the option - out of maybe 200. The kit back then was $7995 (with $300 optional color) so an extra $895 seemed like a lot.