EDIT: Posted the following after looking at your pictures more closely.
Typically on a molded fiberglass camper, the exterior surface of the sides and roof are smooth gelcoat, which is the outermost layer of material formed in the mold. Looking at your pictures, the gray roof surface exposed by scraping appears to have a rough texture. This may indicate the gelcoat has worn away, and in that case, I would apply a coating such as marine paint
to seal and protect the fiberglass.
My observations are my experience with Trilliums and Bolers. Venturas may be made differently. YMMV