John Wyatt makes an interesting comment in a sidebar in his book: "The Americans, and the rest of the world, to the best of my knowledge, call the first bikes 'K0s'. Even American Honda call them 'K0s'. They are not. They are CB750s. The K0 was transition bike, of which 121 were made, between the CB750 and CB750 K1. Honda UK have confirmed this. I believe the confusion arises from the fact that the American market never had any K0 transition models, so the Americans had no need to define the bikes. I think we can all agree that the CB750 and the 121 K0s are the 'early' bikes."
In any case, Bryanj would be right that 11/69 would be the '70 model year. Just like my ride was made in 12/77 and is clearly marked '1978 Model'.
Interestingly, Mick Duckworth divides the models as CB750 (1969-1970), and CB750 K1 (August 1970-November 1971).