I have never seen a Herbertz GAK before. I know Robert Klaas/Kissing Crane did as well (they also offered the fixed blade GAK utility knife), and it was even sold here in a box, but I have never seen one offered for sale. I guess, in part because they don't have a name on the tang stamp, just the pair of kissing cranes as typical. Some KCs don't even have a tang stamp.
Well, it is not quite a GAK, because it does not have the german crest on the scale. More like a civilian version. Actually, there were two versions (see the blade tangs), and I own one of them.
But now, take a look at the original Victorinox introductory offer from 1978 : the crest is oval shape, not rectangular like on the Troopers. Puzzling.