The head "all most" looks like a proto don't it?Cool selector switch maybe it is a specialty ratchet but I would lean more towards a custom job non factory you'd be surprised what someone can do with a lot of so are time fit and finish doesn't really mean it wasn't made.
It could be my eyes deceiving me, but it looks like there may be a set screw holding the swivel extension onto the drive end of the ratchet.I've seen other Armstrong ratchets with the same "mod", which makes me think it was factory made.
The swivel has a roll pin attaching it to the ratchet. The one showed in pescados666's post is most likely what this looked like. What is it?