The Society counts the abbreviation for ha-Shem as an instance of the tetragrammaton (I'm not sure why since it is a surrogate in the same way that kurios is), justifying the rendering of kurios as "Jehovah". That is what is used in Shem-Tob Matthew, which is reckoned as J 2 .
Notice that the KIT misrepresents the facts on Shem-Tob:
"The Shem Tob version of Matthew was made about A.D. 1385. When coming upon quotations from the Hebrew Scriptures where the Name appeared, the translators into Hebrew had no other recourse than to render ky'rios or theos' back into its original Tetragrammaton form . Thus in that early Shem Tob version of Matthew the Tetragrammaton occurs 16 times" (p. 18).
I guess they thought that h' was an abbreviation for yhwh and not ha-Shem. This statement is missing from the 1985 edition of the KIT and a QFR in the 15 August 1997 Watchtower (p. 30) admits that the tetragrammaton is not found in Shem-Tob. But despite this, they continue to claim that Shem-Tob provides "support for employing the divine name in the Christian Greek Scriptures".