well I watched it a few times and although, as you say it's not unadulterated HG , I'm sure (except for one brief section where it sounds like a 3d party warming up offstage, it is a pure matthias. there is a repeater on the riff, i can't remember if Wolfgang makes those with a fretboard or not,,,,, it would be under the keyboard, and it looks like he's reaching very deep. Unfortunately, the camera and the music are too unsynched to tell much about what he's doing. . Also it's too dark where the fretboard might be to tell for sure it's there, but hey available light, etc,etc.
He and Wolfgang showed up at OTW one night and he played on an acoustic, it WAS indeed very impressive. (I only write Wolfgang because I can spell Weishelbau(...something), anyway it sure looks like one of his instruments.