They're pretty easy to find on eBay, in several designs, including a "George Washington hatchet." The hard part is finding someone who doesn't value their more highly than you do. Most of them are touted as pipe cleaner/tamper tools, but I'm pretty sure they're for cigar boxes and beer bottles. My guess is that the hammer is there to tap the nails back in to re-close the box after you've slit the paper seal and lifted the lid using the edged, notched end.