I bought "uncured" rock, and was really worried about it stinking up my house, but it really didn't. I guess it depends on how uncured it really is -- ours was fairly fresh. Carbon in a HOB filter will help with the smell, if you get one.
I think if you're going uncured, you may as well get all uncured, I think the die-off from the uncured may damage the cured. If you want to add cured later, you could do that, as long as you make sure it's cured in another tank (or bucket) before adding it to your display tank.