Pillars of Sais
The Inscribed Pillars of Sais are not referred to directly by Plato. He in fact recounts how the priests of Sais had told Solon (Tim. 27b) that the story of Atlantis was contained in their ‘sacred writings’ (Bury) or ‘registers’ (Jowett).
However, Proclus states that Crantor visited Sais where he was shown a golden pillar inscribed with hieroglyphics that recorded the history of Atlantis. Manetho (c. 300 BC) the Egyptian priest and historian refers to such pillars, claiming that shortly before the Flood, Thoth-Hermes recorded all ancient wisdom on pillars so that the knowledge of the ancients would not be lost in the flood. Josephus the 1st cent AD Jewish historian records a similar story with Seth instead of Thoth.
I should point out that if Plato’s 9,000 years are accepted at face value and the pillar in Sais was inscribed with Egyptian hieroglyphics, then the Atlantis story was originally written in a now unknown earlier script, as the earliest hieroglyphics are dated at the end of the 4th millennium BC, or it had been transmitted orally. In either case there was ample opportunity for errors to have crept into it. Sais existed from around 3000 BC, so it is unlikely that the pillars were written upon with anything other than hieroglyphics. Similarly, if the record of the Atlantis story was recorded on papyrus it was more likely to have been written in the less cumbersome Egyptian hieratic script, which developed alongside the hieroglyphics, again with the inherent risk of transcription errors.
Hecatæus during his visit to Egypt was show 345 statues representing the same number of generations of high priests, which suggested a great antiquity for the priesthood compatible with Plato’s date of 9600 BC for the war with Atlantis.
Plato’s narrative also includes a reference to a pillar in the temple of Atlantis that had inscribed on it the laws by which the empire was to be ruled.