Looking a little closer, although hard to see in the photo... It appears to be a frameless flex retainer. Although quite possibly a retainer and polycarbonate... At that size I'd suspect flex...
Where I used to work we did lots of canopies for enterprise, Ultramar, etc... And I can only think of one time in 8 years or so we did one in polycarbonate... And it was a small canopy. But it's entirely possible...
When I left they started using a new flex from Arlon, in addition to panagraphics and Cooley... Though I don't remember the name of the Arlon product...