Probably the print they used is the same one that was put together back in the late 70s for NBC. Keep in mind that the Saga was specifically made for network television, not for theatrical or video release. Wouldn't be worth them making a brand new cut just to show on AMC.
From wiki:
[In 1977] Francis Ford Coppola asked his editor Barry Malkin to make a 7-hour version for television. .....Malkin also toned down the violence, sex and language for a television audience
There are, however, two other versions which were uncensored
The Godfather 1902–1959: The Complete Epic
The Godfather 1902–1959: The Complete Epic is a reduced, 386 minute version of The Godfather Saga (434 minutes) that was released to video in 1981.[5][6] Lucia Bozzola wrote of this version, "With the freedom of home video, The Complete Epic reinstated the violence that had been edited for television; free of commercial breaks, the narrative drive of Part I was mostly restored, but the impact of Part II was still muted by the separation of Vito's rise from Michael's descent."[7]
Be nice if the last one got an HD or Blu-ray release. That would pretty much be the definitive chronological version since it also includes Godfather III.