Scenting worked well for me one time in a test: I rubbed a fuzzy mouse with a rat, and my corn snake didn't eat it. I thawed out a normal smelling fuzzy mouse, she ate it.
So they know the difference, or at least she did.
I think it's a toss up if your snake will eventually eat the mice on his own. I'd say if he takes them when they are scented like the other type, you've got a good chance he'll eventually take them without scenting. Mind, I've no idea how long that will take. But it seems like he would.