I doubt that Bobby Prince gave false info on purpose. I know John Romero sometimes likes to exaggerate stuff (like the intentional broken secret thing) but Bobby Prince wasn't a part of the id team, he was a contractor. It is such a common riff and it's not as close to the original song that many of the Doom covers are that I can totally believe him going back to listen to it and thinking "I probably made this one before I made the cover stuff" if he didn't have access to the original MIDIs anymore. Remember this game is 30 years old this year.