Modeling the B&O in the 50-60's
Having Japan on the figure base is about as significant - or meaningless - as having Made in (any other country on earth) on the base.
Over the years there have been innumerable makers of 'little people,' ranging from mom-and-pop hobby shops to the giants (which are, in relation to the average size corporation, midgets.) Only someone who regularly collects and trades them would have a clue, and such people would, most probably, be on Japanese-language websites.
I have a few sets of typically Japanese metal figures. They wouldn't win any prizes for artistic excellence (far inferior to Preiser) but they did fill a need when I bought them, long ago and an ocean away. When I need more, I'll most likely use John Allen's methods and make them myself.
Chuck (modeling Central Japan in September, 1964)