Hello Mike!
The handlebar looks like a shortened version of the standard home version. A friend of mine uses a similar handlebar on his '60 A10. It is one of the few remaining parts of his '55 Road Rocket he owned back then. He told me, that the Rocket had been delivered with this handlebar originally (as an option) and that later on he had never seen them for sale again. I agree with you, they look great on the bike, very sporty, kind like clip-ons, but they are not that low. Maybe this is some kind of export-only thing again? Perhaps someone has some more information?
Cheers and a Merry Christmas to all of you,
Markus