https://www.thewrap.com/its-always-sunny-takes-over-the-office-filming-location-video/

“So apparently this is Dunder Mifflin, I guess?” Rob McElhenney says (https://www.instagram.com/p/BzN9roQH1cg) in an Instagram video filmed this morning in the Dunder Mifflin parking lot. “They’re gone now, they’re off the air. Sorry Carell."