Every dealer pretty much uses third party body shops. But this doesn't require a body shop. It'll more than likely be performed by a Tesla automotive technician at a Tesla service center when parts become available.
Ford has a very similar recall on their Ford Explorers. There is a trim piece on the A-pillar exterior that becomes detached and can fly off. But there's is plastic because they aren't complete morons. Either way, they're talking about better glue and one piece of attachment hardware. That's well within the capabilities of an automotive technician.