Sounds like a potentially lucrative investment for the Americans. Japan will likely need a lot of sheet metal in the 1939-1944 period.
I doubt that the Americans extended the same courtesy to it that they did to the Ford plant in Koeln.
One shudders to think of how many Americans died from Japanese guns & bullets whose steel came from the US.
On the other hand, we can only be amazed at how mismatched were the industrial capacities of Japan versus US. Here is a great comparison: