That's what I was getting at, the brim size can be debated for accurracy and importance, but the top part, if it looks too small for the head it's on to fit in it, then it would be a mismatch.
The ribbon on the proto hat lines up with his hair from a front on view, which like I said, the way hats work, the har would get squished under it and it would hug his head tightly. The production ribbing looks to be where his skull would continue from teh part showing, and to fit on his head the top half would have to come in smaller than the bottom. It's too bad the hat was likely cast separate from the head, if they were cast together, any shrinking or expanding would be uniform to both pieces.