When I bake taters, I bake em without foil so the skin doesn't get all soggy. I usually hit em with a lil oil n salt.
I'd say he simply rubbed the taters with oil n seasonings. Since they were red, it was probably some sort of paprika based seasoning (very much like most BBQ rubs).
I watched something on TV and one of the multiple choice questions was
What is the most popular grilled vegetable?
A: potatoes, which struck me as being odd. Maybe their definition is a bit different from mine (I deduced there must be a lot of folks sitting around the campfires with a lot of foil).