You guys might be surprised by what the Japanese were able to do then, after all, they gave the allies a hell of a fright (and fight) in the Pacific.
I have a Japanese carburettor which I think is from that time. It looks just like a Zenith but has a purple/maroon finish and weighs way more than the Zenith. I would guess that not so much was imported. Car had been made in Japan for years by that time.