nice axe, the head does appear to be on upside down (either that or the haft is
) it looks like this is the head that it originally came with tho. (the one in the b&w photo linked is a different style and the edge is still in line for a strike - i agree with atlantia. even if there was a picture, it could also have been put on upside down. on this one i expect the finial at the top may unscrew allowing the head to be removed, or some such arrangement.
i DO have an ancient axe that is so old it's haft has been replaced three times and it's head twice and recently has had both done at the same time.