Nice score, Nick!
Re: the cam lock versus the screw bag connection, I wonder if it allowed for the option of not using a paper bag? Or it may have been that the cloth outer bags had the cam lock, and the vinyl outer bags were attached to the bellows. My guess is that the Sanitaire Tradition cloth bags would fit a Model 260.
We should ask someone in Illinois which models were the 50th anniversary ones and why the green & gold colors were chosen (if they had anything to do with the jubilee). Brian's information is different than what I found in newspaper advertising. I found nothing that suggested special anniversary colors, and the anniversary ads were in 1960 instead of 1959.