First, yes, the common Ford manual transmission knob(s) thread size for a number of years was ½-20.
My original post does not cover what was used by Ford Motor Company on their many assembly lines for the 1962 model year design or how many vendors they had to supply “knobs” or how many tools each supplier may or may not have had. It does not cover all the possible assembly line versions nor any version or versions for offered as a service part while Ford was legally obliged to. Manufacturers were never required to make every given part from multiple suppliers or just tools 100% identical. (I worked in manufacturing 37 years and we often had more than one supplier for some parts and they were never 100% alike for all kinds of reasons. To make everybody do everything 100% exactly in every detail the same would add way too much cost to final products. The finer the details to match the more time and money it takes exponentially. Therefore each drawing or specification had ‘critical to performance’ set of details that all suppliers of a given part had to meet with everything else subject to some extra latitude in being different. ) Manufacturers were never required and still are not required to offer post production service parts 100% the same as production models as long as the same purpose is served.
The post does not cover the known reproductions, some available for decades, nor the sellers that offer at least two different reproductions as new old stock with the implications that they genuine Ford products from the 1960s.
The information provided ONLY covers what our research project found on unrestored substantially unmodified early Cobras and those first Sunbeam Tigers that obtained parts from the Cobra program through Shelby American. In such research restored, raced, and modified all over inside and out cars are of no interest. Anybody can and did do just about everything you can imagine to Cobras after delivery.
Of all the many “possible” 1962 type knobs out there today our research project turned up just a single version on early unmolested Cobras and Tigers. Like most parts, the closer you look the more details you can identify. That makes sense, we have no evidence that Ford sent parts from every one of their mass production suppliers of small parts to AC Cars, Continental Cars, or Shelby American. Based on shipping labels on manufacturer’s parts boxes from Shelby American to customers or dealers, Ford suppliers often drop shipped parts directly to Shelby’s works without having to go through a Ford distribution center. My favorite example: oil fill and crankcase breather caps for 1964 engines in street Cobras. There were at least five different versions of “open” and “closed” emissions caps 1963-64 that look very much the same installed. Looking at one on a car (not necessarily a Cobra) today and a different one on another car later would lead you to believe they were the same. If you find a dozen or so and compare them side by side they are all similar but clearly all slightly different. In my study since 1982 just one of the five versions has been found on low mile and or one owner low mile unrestored Cobras with 1964 model engines. That is not “proof” that none of the other four known versions of that one engineering model “never” made it into a new street Cobra with a 1964 model year engine before retail sale but it is a very strong trend. Did any other caps get used for sure? Based on factory and commercial new car pictures, yes, cars modified or completed by the Shelby American race shop could have gotten one of several 1962-63 caps, the 1964 cap for street cars, or near the end of the Cobra era an early 1965 cap.
Regarding appearance. Original production 1962-65 model years of black ‘plastic’ knobs were not created with a grainy gray appearance to the best of my knowledge looking at them and handling many since 1964. Their appearance does change dramatically over time depending on many factors production and otherwise. Example: When we bought CSX2310 it had a replacement gear shift knob, a reproduction. It was not until 1999 that the second owner of the car contacted me out of the blue and wanted to know where to mail the car’s original to that I knew any “knob history”. The second owner replaced the original knob assembly with a custom one he liked and stored the original. Somewhere between the time he sold the car circa 1972 and 1982 a nice pretty stock type replacement was installed. In 1983 we bought the car and I hunted down a genuine new old stock set of knob pieces in the old blue and gray service packages. Its top section was deep black and extremely glossy. It did not stay that way. The car still uses the knob parts I installed in 1983. (The original mailed to me in 1999 is kept safe in a display case.) Decades of handling, sun, and yes rain from time to time has turned it a dull grainy gray. Will a reproduction age like that? I have no idea, I have tossed the reproductions that were on both our cars as purchased and ones on close friend’s cars in the trash.
It wasn’t a comment by anybody but I toss it in, no matter what version your own study leads you to want, buyer beware. Not long ago a $40ish reproduction of the 1962 style knob was being offered on eBay® for $200+ as ‘nos’ and the picture in the listing looked identical (same manufacturing error) as the low cost replacement offered by a reproduction parts dealer.