AFAIK, the minimum you need to do is change hidden to 1 and resave as a proper cr2 file. Then the dial is gone. I doubt if it's a pre-4.0.3 problem, since they had to edit pre-4.0.3 files in the same manner. But just hiding a dial may cause other problems, so you have to be careful. Maybe you have a specific example of a dial that won't hide, or that warps the element when you make it disappear.