Nice catch Krusty, there is definitely a tonal variation there.
However, it could also be caused by a scuffing by the canopy's lower edge on bare metal. This would cause shallow lateral scratches catching sunlight from above, and giving a lighter appearance from the point of view of the camera.
Also, it looks like the marks are two parallel lines of equal width. They seem too uniform to be from random wear. I wonder if there are a pair of rollers under the canopy that contacts the fuselage sides.