The choke knob on the left is 18415-N3401 or 3601 from 8/73, I believe. The one on the right could be 18415-E4101, E8700, or E8800 from 9/71 to 7/73. One says CHOKE, the other is just the symbol and the part numbers are different between Canada and USA cars. I have no reference to other export variants or the domestic. 18415-E4100 is the early choke knob Kats is talking about. It is unobtanium, the set screw is different, and the mechanisms are also different. There are 11 different part numbers for the mechanism. The choke knob on the left is for mechanism 18410-N3602 or N3403 for Canadian cars. The choke knob on the right could fit in a 18410-E8800 up to 1/72 or E8802 from 1/72 to 6/72 or N3300 from 7/72 to 2/73. The original assembly 18410-E4401 is the choke / throttle mechanism only good up to 1/70. It was replaced by E4601 which came in two variants - braided wire cable and they were replaced with solid wire. I understand the width of the levers is different between models and it affects the slot in the choke plate on the console, but I have yet to document this with my own eyes. Hope this helps! CW-