I really dont know much about the KP1 other than a new version is supposed to be released.

Im fairly sure the vast majority of Knight barrels were button rifled. Cut rifling is usually more expensive and sometimes reserved for odd or custom twist rates. Each caliber and twist requires its own button to be made.

For example, if i wanted a 1-24 twist 45 from Pacnor they would charge me for the button too. Thats like an extra $200. If i order one from Brux its the same price because its single point cut and there is no custom button to buy.

You can choose your twist
http://bruxbarrels.com/downloads/orderform.pdf

You can choose from the twists they offer 450x458 8 groove 10" 14" 15" 18" 20" 22" 26"
http://pac-nor.com/barrels/