On Dec. 4, 1956, Elvis Presley, Jerry Lee Lewis, Carl Perkins and Johnny Cash convened at Sun Studio 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. 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.