'07 Prius Exterior Roof Side Plastic Strips

I guess someone 'needed' it more than I, but the drivers-side black plastic strip on the roof of my '07 Prius is 'missing'. Should I have a body shop take care of this, the dealer, can I do it? It looks pretty straight forward to replace, but I'm concerned about how it's molded to the windshield 'gasket', like it's one piece. Any advice? I want to get this done asap, I'm in Texas in the middle of a drought, but you know how afternoon storms can just pop up, and don't want this to get wet (rust).
Thanks!