Joking aside, my guess is that the earlier cars just had the controller tossed in there on the thin foam sheeting and, due to the controller rattling around in there, they made a running change to stuff the foam block in in place of the foam sheeting.
ChrisB,
I wonder if it was the other way around
My car is fairly early, and was pretty well stuffed with the big block of foam. Could be part of the Touring option, but Tim M. hasn't mentioned it yet.
Jim