I am not 100% sure If I need a permit from the health department for my catering rig if I am doing corporate or private functions only. I am hoping to only need a business license and insurance.
I don't know if you need one either, but to have a permit would make you look more professional, give you some bragging rights, and you could charge a bit more because you are legit.
I would hire a caterer with credentials way before I would hire "some guy" with a smoker.
P.S. Take the health class either way!!!