Hi,
I have attached the best images I can find. They are not great but I will send some better ones in the near future if I can.
Not sure what year your van is but there were two types that I am aware of; the badge on the left is the later type (around 1974-77) and has the word 'FIAT' on a red strip in the middle with a word above and below (in Italian). The earlier type on the right (circa 1970-1973) has the letters 'O.M.' in an oval in the middle. This was the name of the fabricators who made the bodies for FIAT, I forget their name.
Hope that helps for now.
Kind regards,
Andy