Squats and deadlifts will indeed help you forge a stronger core — if you’re doing them right, they’ll have to, because you need a powerful, stable core to produce powerful, stable lifts. But if you’re not also focusing on your core separately, it will likely become a limiting factor in your big lifts. So make sure you’re training your core on its own for the sake of improving your squats, deadlifts, and the overall strength and stability of your center of mass.