Sorry, I should have written my post better, it was the first film they shared an actual scene with. I'm not sure about the coffee shop scene like you said, it could have been done individually but the last scene, hand in hand they were definitely together. I'd say they were together for the coffee shop scene though, simply because they would feed of each other in that moment, and the over the shoulder shots were to capture both their reactions individually and spliced together later. Godfather Part 2, as far as I recollect, they didn't meet each other as their parts were set in different eras and filmed in different countries.