I agree, the "Coal Fired" in the name is a bit confusing. Marco's has two identical Acunto ovens in each of the two restaurants. I've been told they use some coal in the oven used for appetizers and perhaps other specialties. I do know they use wood in the other oven used for pizzas.
BTW, the Limoncello chicken wings from the oven are fantastic!
Since Mark is from Brooklyn, he told me he had multiple samples of water flown in from New York, had it analyzed, and has a machine in the restaurant to duplicate the chemistry of New York water.