the above tank level indicator is a floating rod that has an actual hand with an extended finger in that 1860-1910 "over there" pointing symbol way, and it is currently at E, which is painted on the back window. In the picture above, you can't even see the F painted on under the word Gas, the lighting etc was no good for taking a photo of a letter on a window
I didn't have any idea what the 1923 World's Fair was, and really, it wasn't. None the less, I looked to see if anything even mentioned Ford having trucks there, which of course they would. That they built a round gear shaped building in San Diego for the 1915 Expo, which still is there and being used at the Air and Space Museum, shows that Ford was dedicated to having a big presence at all big events.... and judging from their exhibits at SEMA and other car enthusiast events, they still are.
Anyway, since nothing is evidence of the trucks inclusion there, this claim of being there is nice, but not backed up. Nothing mentions why this truck as a dual sparkplug v6 flathead with Australian heads either, with 3 carbs. So the body might have been in that expo, but the rest is hot rod custom stuff that's not meant to give the impression that this is a restored Concept truck, as obviously, it's all newer parts than 1923... the call board mentions lots of 41 Lincoln parts... nor can we understand what was 1923 concept, and what is the owners preference for more modern hot rod stuff.
there was also a World's Fair in Brazil from 1922-1923, and with the Ford production in Brazil, this truck could have been there instead of the Los Angeles expo. We'll probably not know, or care.