I'm can't tell from the video if they used tape or glue. The stylist just said 'we have our adhesive in place.' A stock unit would be very close to the unit in density but without highlights (highlights are a custom order). Actually those are low lights. They used a color just a couple of shades lighter than the rest of the hair. It's adds a little 'depth' and realism to the piece. A highlight would be a high contrast color typically blonde. The unit in the video also appears to be wet or have product in it.
The hairline in the video is really looking impressive, way better than mine (same specs). Maybe that' s just because the video is only in a 320p resolution?
I talked to Joe and he said it's a custom order. He said that he orders extra light density in the front and light density for the rest of the unit. He doesn't believe in ordering heavy densities. Seeing scalp adds to the realism and I agree. He's a decent guy and there was absolutely no pressure when I went there.