The grey and blu ones, are from 1957, with the camel roof, the white one is later (I suppose 1959) and has a flat top.
As my name can suggest, I can tell you the original plates of this cars: grey one, first owner Camillo Luglio, GE.91334,
the blue one, GE.100336 and than MI.312234; I don't know the original plate of the white one, but now it's PD.888888.