It looks like my wind deflector is missing a pin or a screw holding the hinge together. I have done a fair amount of searching online at various parts shops, and while I have found a diagram for the deflector itself, I can't find a diagram breaking down the components. I'm hoping that my only option isn't a new deflector.

 

It looks to me that you could get a long stainless screw through the top hinged (green arrow) area at the top of the photo and drive it all the way through the hinged pieces.
I'd try and find a long stainless screw