There was a telecast of the gala, possibly on PBS, but I don't remember which network carried it. DG published an LP with /highlights/ from the gala (DG 2530 260} in stereo. The tracks were as follows:
METROPOLITAN OPERA GALA HONORING SIR RUDOLF BING April 22, 1972 Highlights
Side One
1. MARTINA ARROYO Verdi: Il Trovatore "Tacea la notte placida" (cond. Richard Bonynge) 5:41
2. MONTSERRRAT CABALLÉ and PLÁCIDO DOMINGO Puccini: Manon Lescaut, "Tu, tu, amore? Tu?" (cond. James Levine) 8:14
3. BIRGIT NILSSON Strauss: Salome, Final Scene (cond. Karl Böhm) 14:01
Side Two
1. LEONTYNE PRICE Mozart: Le Nozze di Figaro "Dove sono?" (cond. Francesco Molinari-Pradelli) 4:30
2. REGINA RESNIK J. Strauss, Fledermaus "Chacun à Bing's goût" (cond. Kurt Adler) 5:12
3, Richard Tucker and Robert Merrill, Verdi La Forza del Destino Duet, "Invano Alvaro" (cond. Molinari-Pradelli) 8:25
4. TERESA ZYLIS-GARA AND FRANCO CORELLI, Verdi, Otello, "Già nella notte densa" 10:05
... and that's all there is on this LP from that particular gala. The LP was deleted long ago. I don't know about any published edition of the complete gala. --E.A.C.