Choke boring shotguns to improve patterns has probably come around an unknown number of times. Greener, in his book THE GUN, and its developement states the first person he had been able ascertain knew the benefits of choke was Jeremiah Smith of Southfield R.I. in 1827. The idea was patented in England by Pape in 1866. In America the idea of choking guns is attributed to Kimball, a market hunter, but tests found patterns to be irregular in practise. Irregular patterns were gradually improved as the machining skills of gunmakers improved though time. Greener, the English gunmaker, learned of choke boring from a customer in 1874. He worked on the idea and probably did the most to study, understand and to popularize the practise of choke-boring. By 1875 the topic of chokes was very active in the popular sporting press in both the US and England.
The first changeable choke system was patented by Roper in America six weeks prior to Pape's patent. On April 10, 1866 he patented a short ring threaded over the muzzle of a single barrel gun with a short adrupt choke. The idea was dropped as the rotary magazine system of his gun failed to gain many sales.
The POLY CHOKE seems to go back to the 1920's;
http://www.poly-choke.com/