The Godfather Part II (1974)
Firstly, at the end of this movie, in a flashback scene, Sonny suggests Vito Corleone's birthday is December 7th, mentioning that the Japanese dropped "bombs in our own backyard" on their father's birthday. Also, the movie mentions that Vito's father was killed in 1901 and that Vito was only 9 years old at the time of the funeral procession; suggesting that he was born in 1891-2.
The first instance happens when Frank Pentangeli is handed a $100 dollar bill, also known as a "C" note.
The second instance happens in the New York flashback sequence when a young Vito gives the landlord Roberto six $5 bills as six months rent increase in advance for Mrs. Colombo.
The third instance happens when the same six $5 bills are returned to Vito by Roberto after Roberto finds out who he is dealing with. The currency is plainly visible and counted bill by bill in the scene.
This is believed to have been done to show the secretive nature and private emphasis in the Corleone family, unlike other mafia films which always feature many shots of large amounts of money being actually shown. See also The Godfather.