Yes, the Bantam was the original GP. There was a pretty big competition for the contract. It is a little bit funny that a large percentage of the GP' were Ford, built to Willy's specs. That is what I was born in, as was my sister. A '42 Ford GP. Had the little Ford "F" on the bolts and stuff.
I wonder what the success of Bantam would have been if they had secured that contract???
My favorite plane is the F4x series Corsiar. It was built, of course, by Chance-Vought, but also Goodyear and a second company that slips my mind at the moment. Chance-Vought and Goodyear planes saw action. Most planes built by the third company were used as trainers. Chance-Vought simply could not support the volume required, so it took three companies to do it. That was common for many products.
My reference to the vehicle built for US military contract was about the post WW-II Landcruiser. It was in part to build a heavier duty, enclosed cab all weather GP. It was also in part to help in the rebuilding of Japanese industry, in this case getting Toyota rolling.