I think I may have found the one you were talking about.
I thought you meant in the "store" part of the website, and not where they have the historical stuff listed.
So I found this, catalog number 219496 in the British Museum:
The British Museum says that the cylinder tells us: "In 605 Nebuchadnezzar, the Babylonian crown prince, replaced his father Nabopolassar." as well as "Nebuchadnezzar's army besieged Jerusalem and captured it on 15/16th March 597 BC. The new king of Judah, Jehoiachin, was captured and carried off to Babylon."
The Insight book, Volume 2, page 480, under the heading "Conquest of Jerusalem", says this: " Jehoiachin surrendered to Nebuchadnezzar (in the month of Adar [February-March] during Nebuchadnezzar’s seventh regnal year [ending in Nisan 617 B.C.E.], according to the Babylonian Chronicles). A cuneiform inscription (British Museum 21946) states: "The seventh year: In the month Kislev the king of Akkad mustered his army and marched to Hattu. He encamped against the city of Judah and on the second day of the month Adar he captured the city (and) seized (its) king [Jehoiachin]. A king of his own choice [Zedekiah] he appointed in the city (and) taking the vast tribute he brought it into Babylon." (bold mine)So do you see what they did there? They deceptively use the tablet, give credit to the British Museum as the source, and then MISQUOTE it regarding Nebuchadnezzar's reign. The British Museum's scholars as well as:
T.C. Mitchell, The Bible in the British Museu (London, The British Museum Press, 1988) A.K. Grayson, Babylonian and Assyrian chroni (Locust Valley, J.J. Augustin, 1975) D.J. Wiseman, Chronicles of Chaldaean kings (London, Trustees of the British Museum, 1956) J.B. Pritchard, Ancient Near Eastern texts rel, 3rd ed. (Princeton University Press, 1969)
and many, many others all attest that Nebuchadnezzar's reign began in 605BCE. But in order to make history and the Bible, which confirm each other nicely, fit their theology (LOL), the Watchtower has to use deception to make their members think that Nebuchadnezzar was king in plenty of time to have made a conquest of Jerusalem in 607BCE, therefore marking the beginning of the 2,520 years at a point that will arrive at their 1914 date. Thanks for point this out, KW. This is even more devastation to the theological scandal that the 1914 date has turned out to be.