Press 'L' for Landmark; Time & Life Lobby, a 50's Gem, Awaits Recognition
Time & Life Building lobby, whose gray-and-white serpentine swirls recall Rio's Copacabana, is set to receive landmark status; Frank E Sanchis III, executive director of Municipal Art Society, is credited with convincing owner, Rockefeller Group Development Corp, that architecture of 1950's is worth preserving; space was designed by Harrison, Abramowitz & Harris; photo (M)