>> Didn’t a bunch of individuals get together and just agree on what books to add, or not add? If so, then there was no ‘original text’. Not like the book just fell out of the sky complete. <<
I meant the original text of the Book of Kings, which is several centuries older than the chapter known as the Testament of Solomon.
If you’re curious about “a bunch of individuals,” the Orthodox Old Testament consists of those books which had been translated from Hebrew to Greek about two centuries before Christ. The Jewish bible consists of those selected by the Council of Jamnia, a few decades after Christ. The Protestant bible follows the Council of Jamnia. The Catholic bible follows those that the Council of Trent must be defended, which is very similar to the Orthodox bible, but excludes a shorter version (called Greek Esdras or 3 Esdras) of Ezra (1 Esdras) and Nehemiah (2 Esdras), which was allowed to fall into disuse because it contained no new information.
Actually, you should to read more research about the so-called "Council of Jamnia." as well as the LXX.