Lovely truck!
I do have to comment on the grille; It's not a specific Ford grille. Cab 11's, Ford and Chev, used the same style grille made of woven mesh. The Diamond pattern style grille for Chev's wasn't introduced until cab 12 production and even those sometimes had square mesh or even a combination of diamond and square woven mesh.
My Cab11 C8 also had the keyed ignition, so it could be that these were also used until the later part of 1940, although mine could have been added later in it's life.
David Hayward did have the truck in his files; which can partly be found here:
http://hotrod.gregwapling.com/chev-t...dian-chev.html