In Italy, Sicily and Sardinia, the correct way to indicate 1 is a thumb. Wouldn't the 2 be a thumb and index finger... and not a index finger and middle finger?
Even though Fanucci is a Sicilian in the novel, in the film's screenplay he is a Neapolitan. Perhaps therein lies the answer?
"It was between the brothers Kay -- I had nothing to do with it."
