Welcome to Pellet Fan!
It is Pit cooked, so you have to determine what that means. To me it lends itself to a pellet unit, slow roasted in pit, then sliced thin and served on white bread or roll. A great sandwich, but just another take on a roast beef sandwich for me.
I knew about the grilling, what it came down to was it was usually cooked over wood coals of some kind. I still think most pellet units are capable of both. I still think it is more roasted then grilled like a Santa Maria Tri-tip...
What I have learned is there is 50 ways to do everything and about the same amount of names for a roast beef sandwich!