does the saga always have the violence and nudity censored?

the Saga is made for TV - so - yeah.

Plus,the TV censors made some amusing bowdlerizations of the dialog:
--Sonny says, re. planting the gun: "I don't want my brother comin' outta there with just a stick in his hands."
--Pentangeli tells Michael re. the Rosato brothers: "Clemenza promised them ushgotz."
--Bonasera tells Vito, re. the two kids who beat his daugher: "And those two punks,they smiled at me."

Especially when Frankie is telling Michael all the terrible things that the Rosatto brothers are doing back in New York.

...spitting in their grandmothers' neighborhoods...

I think it got a little racier during Michael's marriage night scene....they sort of blocked out her nipples, but it was better than nothing.