I see there's no barrel bushing.
In the slide locked back pic on the video above, you can see a darker ring around the larger diameter of the bull bbl. Maybe its an all new design OR the basic 75 type bushing. The front sight goes in with a side-to-side dovetail mount that appears to go pretty deep /close to that bull bbl. Just maybes.
Second and third look: I think it's a version of the ACCU Shadow bushing.