I agree with Robert. That said, if this was a budget repair, and most of the money was spent on the cab repairs and little was left for the fenders. The fenders could be changed latter as money became available, painted to match, etc.. One way to fix this area would be to coat both the inside and outside of the areas with an epoxy based resin/fiberglass, like WestSystems, as opposed to a polyester based resin that may not hold up to the expanding and shrinking of the metal in the heat.
