I agree with lieblad, I have a Marshall wells zenith double bit that has the makers mark printed upside down, or at least I'm pretty sure it is. The eye is the same size on both ends and the bits don't seem to be worn down as much, although when the makers mark is oriented the correct way it definitely looks to be upside down. Not exactly the same as what you're dealing with but depending what it was used for it could very well just be worn down so that it looks like it's correct but it's really meant to go the other way. There are axes that both ends of the eye are equal size like my zenith but the majority are smaller on the bottom and a bit larger on the top to account for the wedge widening it, and I've yet to see one that truly was smaller on the top.