I forgot to mention in my Frontier/Elvis post above that Gerry Seible had a very good run as an amateur boxer. Per him, he is the only person ever to beat Sugar Ray Robinson in his amateur career. Gerry says Sugar Ray creamed his as* in a rematch.
Gerry brought Sugar Ray to the Frontier on an exhibition tour. Sugar Ray sparred 3 rounds at the Silver Slipper where this picture was taken. Joe Louis was there as you can see. The 4th person is Billy Conn, a light heavy weight.