I took that to be part of the long running gag of referring to them with the wrong names because someone thought they must have heard wrong.
Beavis is a real name. The Monty Python lumberjack is a Beavis. Don't gotta change that one. Butt-Head....y'know, they've given enough clues over the years that their moms are semi-retarded fish-drunk groupies, and we know their dads are those two roadies from the first movie, so I can totally believe Butt-Head is his legal name.
Damn.... watched an episode from Season 2, the cut scene had a very old music video by DJ Jazzy Jeff & the Fresh Prince: Girls Ain’t Nothing but Trouble. I haven't heard the song in a long time, close to thirty years.
Still digging it. You can see the thought process leading up to the new material. "Should we make them old, or bring the boys into the future? Fuck it! Parallel universes!"
Usually when people on SNL can't stay in character and control their laughter, it's, at the very least, annoying. This time, though, somehow it made it better.