I also heard and saw movies where the "666" thing is "supposed to be" 999" .
I do plan to tell PRS, when I order my guitar, not to give me a serial number with any of those sequential numbers in it.
Many scholars agree that the reference to 666 was code for the Roman emperor Nero, who murdered lots of Christians, and held them responsible for the fire in Rome. Neron Caesar written in Hebrew produces the number 666.
You can imagine how early Christians related to the dude who was murdering them, but speaking out against an emperor was a guaranteed way to get executed, so code was necessary.
I don't believe in supernatural beings, so I regard this stuff as interesting historical trivia and nothing more, but I enjoy reading about it.