They are probably cataloged in a well known reference. Once your book is published (and maybe donate a copy to NGC's reference library) you might be able to get them slabbed by submitting them and referencing them as "in the reference "Book title" by authors name."
From a layman view. Clash is there for all too see. I agree that your coin has a different date. Yet, does NGC, or even other graders have hundreds of those same coins on hand to compare too ? I think you are looking at it all from YOUR POINT OF VIEW. Think about it in general. Look at a clash die, bingo - its there. Show me a coin with an off date, how would I even know if it were one coin I have only seen 5 examples of in my whole life.
I would bet that in South Korea a coin collector would know a lot more, and they may very grade it at NGC (niko-gradin- corp) of korea... if they have one. It is just this is America JACk, and they dont care. Now, if Korea owned the reserve currency and had our corrupt Banksters as their leaders of the south korean FED, they it would be important.
There are literally thousands of errors and varieties that NGC and PCGS will not attribute and put on a slab label. And it's not only world coins it's US coins too. ANACS and ICG will slab and label more errors and varieties than the other two will, but not even they do all of them.
Op's narrow date coin mapped in CAD. Then overlaid onto the wide date. Not only is the spacing narrower. As expected the placement of the date is shifted slightly. But also the "1", "9" and "9" date digits appear to be slightly larger on the narrow date.
Incredible! Thanks for rendering their differences in CAD! You can really see how different they really are, especially in shape and vertical placement...