tkgdisney,
I don't really know the answer to your question, but I just wanted to let you know that even if the refurbishment does finish early, the Matterhorn is a ride that seems to break down frequently, so you may want to prepare your DS (and yourself) for that.
It seems like everytime I visit, it's "broken" for a portion of my time there. They always fix it sometime during the day, but it's frustrating to be in line when it breaks, then have to make the decision to wait or to come back later.
(Sorry, didn't want to be the bearer of bummer news, but it's better to be prepared!)