Hi Michael,
Looks like a regular J-hook (or is that a G-hook) belt attachment with an extra long "leg" tab on it. Because they have the mounting holes centered halfway down the vertical axis of the sheath, the top of your belt rides pretty much level with the top or the bottom of the sheath pouch, depending on which way you mount the hook to the sheath.
To quote the link, "the sheath has been built to accept the Blade-Tech TekLock buckle system". (emphasis mine) So they don't actually give you a Tek-Loc, they have just drilled the sheath pouch such that you can mount a T-L to it, should you choose to do so.
That's my read on the pix/info anyway,
Greg