* Production Numbers: Precise production figures for the 1926 Chevrolet Superior K are likely difficult, if not impossible, to find with certainty. Chevrolet's record-keeping from that era wasn't as meticulous as it is today.
* Survival Rate: Many cars from 1926 simply didn't survive. Factors like rust, accidents, and parts obsolescence have taken their toll. A surviving Superior K would be considered rare simply by virtue of its age.
* Condition: A restored, concours-condition 1926 Chevrolet Superior K would be far rarer than a dilapidated, parts car.
In summary: While not necessarily exceptionally rare compared to some other vintage cars (especially those with far lower production numbers), a 1926 Chevrolet Superior K is undoubtedly a rare classic car due to its age and the number of cars that have been lost to time. To determine its *exact* rarity, you'd need to consult with Chevrolet historical societies, classic car databases, and potentially even experienced appraisers specializing in vintage Chevrolets.