Yes - but the affect would be ever so slight and tiny that it wouldn't be measureable. If you were trying to move the hull through air closer to the speed of sound - yes, it might make a measureable difference. However, at highway speed, the resistance due to airflow is more about profile drag than skin drag...and when changing the finish of a suface on the magnitude of these coatings, you would be affecting skin drag.

Skin drag is largely affected by how thin/thick the boundary layer of turbulent airflow is between the skin of the object and the smooth laminar air flow around the object. There is so much outside turbulance coming from other cars, the tow vehicle, and cross breezes that your not going to get a steady boundary layer no matter what you do. Hence the skin drag (through air) can't be significantly impacted by a coating on this level and at these speeds.