Jayco X19H Roof does not support weight of solar cells?

Does the roof plan state what the base material for the roof is? 3/8" plywood or possibly some foam based material that will not hold fasteners well enough to ensure the panels don't pull out when reaching highway speeds.

They may have used something like a masonite panel which could make your panels pull the fasteners when they try to lift due to wind passing along the roofline.