Yes that is a 21" pixeltouch. It is mounted to the original monitor shelf. It looks great from the front, it only pokes out from the back. The way I am going to line my games up should hide it.
The original monitor was actually larger (23"), but those monochrome monitors have really shallow tubes, and thus they fit perfectly in that cabinet.
ANY normal monitor would have poked out the back of that cab. The darn thing is almost a foot shallower than a normal Pac-Man or Defender (or whatever).
I also have the same model of monitor massively poking out of the back of my Artic Mini as well, and plan on poking the 3rd one out of the back of my empty video poker cabinet, which is going to be a vertical trackball cabinet (only like a dozen games are vertical trackball, but they include a few really good ones, Centipede, Millipede, Capcom Bowling, and Quantum).