"Classified" supersonic aircraft?

This from the latest AW&ST

"SECRET STREAKER?

On the morning of Jan. 7, an aircraft using call sign "Lockheed Test
2334" told the FAA's Albuquerque Center it would be "going supersonic
somewhere above Flight Level 60 [60,000 ft.]" for about 10 sec. It was
flying over the Pecos Military Operating Area in eastern New Mexico at
the time, transmitting on 350.350 MHz. When a center controller
queried, "Say aircraft type," the unidentified vehicle's pilot
responded: "We are a classified type and can't reveal our true
altitude." About 15 min. later, the same pilot--on a different
frequency (351.700 MHz.)--requested permission for a descent to 30,000
ft. and flight-following to "Las Vegas with final destination
somewhere in the Nellis Range" complex. The U.S. Air Force's
super-secret Groom Lake test facility is located in the northwest
portion of the Nellis AFB, Nev., ranges. The Albuquerque Center
controller quipped, "Trip home a bit slower, eh?" There was no
response from the classified aircraft. The radio interchanges were
recorded by Steve Douglass, a "military radio monitor" hobbyist in
Amarillo, Tex."


Couldn't this just be a plain old F-22? Going over 60k is nothing
special. The part about "can't reveal our true altitude" sounds like
BS. If they can see them on radar I'd think they'd be able to tell
how high they were.