No one believes the 607 date. Anyone doing a modicum of research can prove otherwise. I found this in 5 minutes:
The Bullae House, east of the House of Ahi'el, is so named for a collection of almost 50 clay sealings (bullae) with Hebrew lettering found there. The floor of this house, only partly excavated, was covered by a thick charred destruction layer containing the bullae as well as pottery vessels, arrowheads and limestone cult stands, all of which attest to the character of the house as a public building. The finds are typical of the final stage of the Iron Age and the bullae found in this context clearly date to the Babylonian destruction of Jerusalem in 587-6 BCE. The bullae, made of fingernail-sized lumps of soft clay shaped as flat disks, were affixed to a string binding a papyrus document and then stamped with a seal. To open and read the document, the bulla sealing had to be broken in order to separate it from the string. The conflagration that destroyed the house and burnt the documents stored in it also fired the clay of the bullae, thus preserving them in very good condition - fully legible. They bear dozens of Hebrew personal names, two of them belonging to personages known from the Bible. One is Gemaryahu son of Shafan, a high official at the court of King Jehoiakim of Judah who reigned on the eve of the destruction of Jerusalem by the Babylonians:
Then Baruch read from the book the words of Jeremiah in the house of the Lord, in the chamber of Gemaryahu the son of Shafan the scribe, in the upper court at the entrance of the new Gate of the Lord's House in the hearing of all the people. (Jeremiah 36:10; see also 11-12, 25)
Here's the link: