I thought about that too - one of the assasins that young vito didn't get - but if he was seeking revenge on his father's assasins, and Vito's father supposedly died in 1901 - and if GFIII happened in the 1979-80 timeframe, then those assasins would be pushing 100 years of age by that time.

I'm thinking Mosca has to be present during Michael's young Sicily days - but I can't figure out who, or where.