And unless the perspective on this is wrong, roughly half of the lower hemisphere is open, while both ears, when you put them together, form a shorter arc, roughly a semi-ellipse. A quarter of a sphere and a semi-ellipse don't make a full sphere.
Not to mention that it isn't made explicit just how you could place something that is on the very crown of the head past the giant gear of the head, the body, the rather long arms (and the wide shoulders) and the upper hemisphere inside the dress so the ears fit into the hole.
Believe me, sometimes, a cube just doesn't go into the obvious cube-shaped hole; it's a common formal operation, to subtract a volume from another volume and place it somewhere else.
I'm not saying it's definitive (the pokeball patterning is very suggestive, which is why everyone is so convinced; I assure you that without it, nobody would notice the shape of the ears), but from what little we can see, I don't think the ears have the necessary profile, or the means, to fit down there.