I jest you not! I was a nin fan before ever playing the game so I was tuned in when I first saw the logos in game. I think if you go back and play even the first level of Q2 you’ll see them. He did 1 also but I’m not sure there were logos in that. It’s even listed on the Wikipedia site if that confirms that I’m not full of crap.
Fyi, quakes’ music and sound effects were made by Trent Reznor (nine inche nails). There were definitely nin logos in Quake 2. He described the “music” not as music but ambient sounds to make things creepy but also contributed the sound effects, presumably for the shotgun also.