I took more pictures of this canopy. https://link.shutterfly.com/qI0hDPifPbb.
Some additional clues;
– The window does have additional holes for a sliding Mecaplex-type window.
– The bottom of the canopy is not flat. Towards the “aft” (I think) end of the canopy the bottom edge tilts upward. But the bottom edge of this portion is flat and does not have the curve of a leading edge.
Any more ideas? Hate to throw this nice canopy out.