Headers are easily spoofed. Scam marketers do it all the time.
Even if it was from an FAA official, it would have been contrary to policy.
From Bloomberg Business, 4/14/2015:
Federal regulators will stop sending scary letters to drone hobbyists who post evidence of airspace infractions on YouTube
YouTube is blanketed with crimes against American airspace committed by private owners of unmanned aerial vehicles, which hasn't escaped the notice of officials at the Federal Aviation Administration. In recent years, the agency has sent letters to scores of drone hobbyists who published videos in which federal flight rules have clearly been violated. Panicked recipients often pull down the proof of their infractions.
That cat-and-mouse game has come to an end. As part of its kinder, gentler stance toward civilian drones, the FAA has set a new policy against involvement in most cases involving drone hobbyists with YouTube hits. John Duncan, director of the FAA’s Flight Standard Service, told inspectors last week that they have no authority to order or suggest that drone videos posted online be removed. A video “is ordinarily not sufficient evidence alone to determine” that a drone flight violated federal rules, he wrote in a memo.