The Model K Codes
As others have referenced, the Model K movements are marked with a code on the pillar plate that signifies certain characteristics. This was previously summarized by Bob Olson in a brief production history of the company. While mostly correct, I believe there are notable inconsistencies in what has now been accepted.
The two digits represent the movement configuration.
10: Open Face
This is consistent. However, after studying other New York Standard grade classifications, I believe that only the first digit represents the configuration, but since the first digit in the code is always followed by a “0,” this point does not matter in practicality.
Mr. Olson reports the next digit represents the hand style, “1” for spade and “2” for moon. This is somewhat true. However, based on recorded observations, I believe this digit reflects some other trait that is incidentally paired with these hand styles. Additionally, only the 12-Size movements seem to align with this convention. And even then, both moon and kite hand styles are paired with the “2.” I have not yet been able to derive an alternative trait for this code. Interestingly, all the “2” digits I have recorded have been 7-Jewel movements. The “1” digit is mixed with 7-Jewel and 15-Jewel.
The next two digits indeed represent the size, as Mr. Olson reports.
The last two digits have been assumed to represent the numeral style of the dial. However, enough observations have been recorded to refute this claim. Identical dial styles have been logged with different codes and very different styles with the same code. There appears to be no relationship between the last two digits and the dial other than a loose trend progression. For that reason, I believe these digits may be related to production sequence instead, possibly the year of manufacture.
Recording more observations of the Model K watches and various attributes may provide additional clarity. If you happen to have watches that have not already been added, especially if they contradict the above information, please feel free to post images.