Well, let's face it, the Reserve Officer was probably called on duty because the carnival was in town: "We need some extra help from you Reserve Officers because we expect a higher number of incidents. So keep your eyes open."
So he was probably "primed" for such a thing and didn't expect to see a phone truck rolling that late. And no doubt your truck has a lot of copper, tools, communications equipment, etc in it.
So, yeah, I could see him pulling you over. Sorta.
Forgiveable overzealouness, perhaps, but it beats underzealouness in this case.
Too bad about your not being able to carry your personal self-defense firearm on duty. Sux.
Terry, 230RN