Emerson, Lake & Palmer may have performed on this day in 1974 at the Municipal Auditorium in New Orleans, Louisiana.
The date, as some of the others on their Brain Salad Surgery tour, is disputed. I have been able to find no material evidence that this concert took place, and at least one website I use questions its existence. Immediately prior to this potential concert, the band had been in Baton Rouge. They would not perform another confirmed concert until significantly later in March.
There is no known recording of this concert. If there were, it would clear things up about this potential date immensely.