Yep
Nope. They used 2 or 3 digits without what we are used to as the third digit after 1949.
23 is February 1943, 116 is November 1946 and so forth. In 1950 they Bagan using the 3 and 4 digits (only in October, November & December) which we are used to seeing. I am told that the codes were absent until near the end of 1941, the lowest I have seen is 91 for September 1941.
But this means that the example you gave for "301" would not have existed, never mind meaning January, 1943, which would actually be represented with "13".
Yep, true. I was recalling something that I later confirmed to be incorrect, it is a different pair and does have 13 on it instead. The deck that I thought was the one I was thinking about at the time in fact has has 103, which should be October, 1943 according to everything that I was told. I have numerous examples of decks with 2-digit and 3-digit codes that have Bakelite cases, and a very few with genuine Bakelite (the later cases appear to be the same, but have a small "KEM" with a crown branded over the top instead of the stretched out K - E - M across the entire surface from top-to-bottom) which have 3-digit codes indicating manufacture between March 1950 (350) and April 1954 (454) as well as two with 4 digits - 1052 (October 1952) and 1251 (December 1951). All of those that I have found with date codes beyond 1955 (155, etc - and later) are not Bakelite, or are the later side-by-side (flat) cases as opposed to the earlier two examples, bakelite pre-1954 and normal plastic (non-phenolic, in other words no 'odd' smell) from early 1955 on. I don't have enough empirical evidence to surmise when the precise change occurred, although this does narrow it down to some time in '54 or '55. That makes sense because as I previously noted Union Carbide (and Carbon at that time) bought Bakelite Company and incorporated it into their brand in 1948 and I suspect that Kem likely had enough of the cases already on-hand to last a few years, apparently quite a few - about 5 or 6 years' worth at most. It would be interesting to do a survey of Kem decks to narrow that down, as I would have to assume that there was a short period that certain decks were placed in both type (Bakelite or not) containers that on the initial inspection appear to be very similar (except weight, which is drastically different - phenolic plastics are made using formaldehyde which incurs that funky odor as well as they higher weight from the process) and the close inspection of the lid shows the older Bakelite lids have that broad top-to-bottom K-E-M as opposed to the non-Bakelite tops with KEM in 1" high (approx) letters surmounted with a crown.
I suppose that there is a period later where certain decks were in the latter boxes or the flat cases as well, but again I don't have many (2, possibly?) of those and both are 1960's as I recall. I have one deck with no codes whatsoever - the one in the OP.
One other thing that I have recently noticed that I hadn't though about until then was that the date code appears below the left lobe on the AoS in odd months and below the right lobe in even months on the AoS in post-1950 decks, I suppose to eliminate any possibility of misinterpreting that code? Not certain, again, I only have maybe a dozen examples, and only 4 or post-1950 dates. Most are the 2-digit and 3-digit 40's codes and this lone example contains no codes at all.
One more thing I just noticed by comparing it to another Bakelite case, this one is not only about 1/8" less tall, it is also about 1/8" less deep (back to front) but the side-to-side dimension is almost identical. Again, I have never seen another case where the top "dovetailed" into the bottom as opposed to the opposite.
