Some of the later models with the chain brake assembly had the bar with a lettering. <-- not that I've seen one in person just going by this image..
I think the earlier models had a plain steel bar - no lettering - just a small stamped part number.
If my memory serves me right, those hultafors axe handles are just about an exact fit for 4 1/2 pound HB axes..should not take too much for a great hafting.
Great find Jethro (the 7-10A). I think it's as good a time as any to post a pic of my 3 macs. The 7-10A is awesome I was lucky enough to find one a couple of years ago in Melbourne Victoria.