Um. Not really. The interior of the airbox will always be at a lower temperature than the exterior, so you are simply limiting heat flow into the box.
The temperature of the airbox will stabilise at a point where the heat flow into the box equals the cooling effect of the air passing through. If you insulate the box, then (assuming the same air-flow through the box) the temperature rise of the air flowing through the box is correspondingly reduced.
Basically, if your insulation reduces the heat flow into the box by a factor X, then you will reduce the change in the intake temperature passing through the box by the same factor.