Is K4 a Runic Cipher?
Of course not.
I did find a very brief crypoanalysis challenge at the FBI site from 2009 though. The punchline has already been ruined but it’s interesting they went with this and put the message they did.
Elder Futhark, the Younger and to a lesser extent the Anglo-Saxon Futhorc were interesting to look into. With Kryptos K4, it’s either English or some Latin descendant and not some Runic alphabet. It is interesting in a different way that so much of old cryptanalysis involves the study of language and the analysis of language as much as it involves the ciphers and codes. Compare that with modern ciphers like RSA and it’s the switch from language to math. I’ll leave it to you to decide which will be more fruitful with K4. You would think modern analysts would have a much greater advantage with the latter but that the tools would be in place with the former for us neophytes. Could be some hybrid or transitory precursor that Scheidt suggested for the overall feel of the cipher systems.