They use Physical Vapor Deposition (PVD) using a hard vacuum to put the silly decorative metallic finish on plastic kitchen blenders; it becomes economic with large quantities. And very nice antireflective coatings are commonplace in camera lenses.
With that in mind, I'd be very surprised if the glass used in solar panels wasn't coated (at least on the underside) -- it seems like a very easy efficiency win for a very low recurring cost? I know the glass panels are larger than camera lens elements, but still.
Also, regarding antireflective coatings being delicate: yeah, making a coating that is both durable, not overly sticky, and antireflective is a difficult compromise. But don't forget that the underside of the glass is a potential reflection point. Even if they only coated the underside of the glass, that still halves your reflection losses, and the side of the glass that sees the outside environment is dead-standard uncoated glass (or differently coated).