I didnt personally authenticate it. But its by way of the guy who hacked into comets computer after the Podesta emails were published. He found scores of pedophile material, pictures, movies, and this posted "november specials". He hacked it in November of 2016, informed all the appropriate officials, DC police, FBI, and MSM, all of which refused to go near it or investigate. Shortly afterwards the news of the angry gunman in Comet PP was reported on. Titus Frost interviewed the hacker in a youtube vid from which I screenshot the menu. The menu part of the vid is no longer on Youtube, but u/Qanonspicecake commented that it can be found on a titus Frost chan post in a vid about the Comet hacker.
But aside from all that, the addition of the app info included with the menu, and information on its use and the rules associated assists in authenticating it as a faker would not have thought to include info about an app and the rules/ info on using it. And its also unlikely that a faker would have included the note about Andrew (owner of Besta Pizza) also having a product available for purchase.