At the time this movie was made (1945), three balls indicated a pawnshop, much like a red-and-white stripe indicated a barbershop.
According to a 1910 almanac: The three golden balls used as the pawn- broker's sign appeared in England at a very early date. It was used by the Lombard merchants who emigrated to London from Italy. These established the first pawnbroking establishments, and it is generally held that they adopted the three golden balls to be borne of the arms of the Lombard corporation, from the armorial bearings pf the Medici family, which was conspicuous among the Lombard merchant princes of Italy.
