Raleigh, on the "Tourist" models more than some others, tended to maintain the older features for quite a bit longer than most companies might. I had a '77ish Nottingham Sprite that had the same crankset. Raleigh was never in a hurry to change anything if the old stuff still worked. They did afterall, keep making the DL-1 into the 1980's and it's hard enough to tell a 1975 or 1980 "Sports" from a 1955 version.