Last evening at our bridge session, one of our opponents switched from nominating by speaking to nominating by pointing. All my partner and I could say positively was that he pointed to a line of clubs in dummy. Dummy played the Ace of clubs and we all followed suit. Declarer then stated "I pointed to the 8 and not the Ace". The Director was called and ruled that the 8 could be substituted for the Ace and my partner and I could change our cards if we wished. Was this correct and is nominating by pointing acceptable? I should add that dummy was not at all hard of hearing.