A simple AR coating (just 1 or 2 layers) is not expensive. You can get this on windows at a rather low extra costs. Coating window panes is standard (at least in Europe) - in small quatities you may have to pay extra for an uncoated gals.
Even if its only some 3 % of more energy gained, the cost of the coating is likely less than 3% of the panel, and higher efficiency panels also need less area and mounting.
Sould not be a golf ball, as the panels should withstand hail of comparable size and weight und thus therminal speed. This one looks like not just shatterd but way over the design limit.