On Dec. 4, 1956, Elvis Presley, Jerry Lee Lewis, Carl Perkins and Johnny Cash convened at Sun Studio — or Sam Phillips’ Memphis Recording Service, to be precise — for a more or less impromptu jam session and intermittent epistemological debate that came to be regarded as a milestone moment in popular music lore. The so-called “Million Dollar Quartet” session has been celebrated ever since, on record, in books and on Broadway. Four days later, five teenagers from East High School entered the same space at 706 Union Ave., gathered around a single microphone and recorded two takes of an original song, “Steady Girl.” Their effort never was released and immediately was forgotten.