Pretty much - although at times the divide is pretty academic. Several characters have been able to do things like STAB IDEAS TO DEATH WITH A KNIFE, and that isn't magic - Death is the normal end of things, so it's an unusual route to the possible, and thus isn't Magic.So there's a line between Sorcery, which breaks normal Cause and Effect, and Magic, which breaks normal Possible and Impossible? Interesting. I take it the Grail was a bunch of Sorcerers bootstrapping themselves up to a full on Magic effect. Only because Sorcery still has limits and rules there's all sorts of conditionals on it, and human greed means the once polite contest to see who was most deserving has turning into an all out war.
Also, there are only Four Mages alive, and only three know active, although it's possible in universe to touch the edges of a magic (one of the scenarios has a character re-create the Mystic Code of the Second Mage, which allows limited replication of his magic). All the Mages also use Sorcery, as Magic tends to be pretty focused.
And we havn't even touched on the Marbles/Boundry effects!