I was told by the previous owner of my 1930 Tudor that it was a Canadian car. Not until I found this thread did I think it actually was! My car has Robertson head screws in this panel, and in the door jambs as well.
I showed my friend who's a designer at Ford of Brazil this Fordbarn post. When he replied he told me about a book on this topic: http://www.amazon.com/Fordlandia-Henry-Fords-Forgotten-Jungle/dp/0805082360?tag=atomicindus08-20