Ford USA stamping did not start to appear on tool items until after 1931'.
Early V8 tools often had ''40 , 81A or 01''.... [ '33 to '37; '38 & '39; post 1940...].
In the Model T era & for 1928 Ford script [ no USA] was stamped but then script was removed until late '31 when all the Ford USA & Made in Canada items start.
For Model A tools, finding the correct ones with only suppliers markings, no Ford script, is the tricky bit.