I interpreted the palimpsest wrong. K2 suggests the date of 9/24 and not 9/23.
I think K1 establishes that the upper-left quadrant is in fact a palimpsest of a calendar with format rows = December(top row) and columns = 1 up to 31. K2 is "LAYER TWO", an instruction or hint to put two things on top of one another. I believe K1 contains two important points: 1) that which is between subtle shading and the absence of light, and 2) the coordinate date of 11/26 at the position of the Q of IQLUSION. Point 1, I believe is describing the Sun and a condition where it's light becomes absent: a solar eclipse. This becomes important when we think of the meaning of "layer two," which may be interpreted as layer the Sun and the Moon, thus describing a solar eclipse. Point 2, I think that's pretty clear as it relates to the journal entry date of Howard Carter's discovery of King Tut's tomb, which we recognize as K3 after the double rotational transposition.
K2, the date I'm now most comfortable investigating as relating to the U of UNDERGUUND, is 9/24. Clearly there was no year information to be extracted out of K1 when it came to finding the 1922 date of Carter's journal as applied to K3. There is also no year date to be found in K2. So, what could be the point of K2, and what year, if any, does it apply?
I have an idea. If K1 may be interpreted as describing the event of a solar eclipse, then perhaps K2's 9/24 date cooresponds to either an important date of a solar eclipse or the date of a new moon, which is a condition necessary to effect a solar eclipse.
On September 24th in the years between 1900 and 1990: no total solar eclipses occured. In the case of Lunar events, the only new moon to occure on a Sept. 24th was in the year 1919.
In 1919, one major occurence of a total solar eclipse occurred and resulted in the widespread fame of Albert Einstein as it allowed the test of his theory of General Relativity which involved the physics of light bending a specific degree as a result of a gravitational field and which was different than what was predicted by the classical Newtonian model. A flurry of telegraphs and reports propagated around the world's news sources of this confirmation of Einstein's theory.
I don't have any strong evidence that this particular investigative path is what Kryptos is about, but I've got nothing else to consider at the moment. At least Einstein did have strong ties to Berlin. This is purely speculative at this point. I wonder if the point could be made that Sanborn was trying to imprat some sort of wisdom in his creation. He could be saying that a secret message is only as good as the truth it contains and truth is something relative to the observer.