Been sitting around waiting for me to use it. Has some dust on the lens that need to be taken care of, but that's it. Has the front mounting flange, but not the traditional jamming-type flange, so one could still non-optimally front mount it to a board as it is.
The indicator of the external aperture scale connects to the aperture ring of the process lens with screws. The screws thread into the tapped holes in the aperture ring.
The 305/9 APO Nikkor lens threads into a 72mmφ x 1.0mm flange and the flange mounts to the camera.