I've looked for it too in my wheel references and have come up with nothing. My 1953 Kelsey-Hayes catalog shows a similar hub cap mounting, but not on a wheel that looks exactly the same, and not in a 15" x 5" size. Have you looked for numbers or a manufacturer marking on it? Few, if any, of the vehicle manufacturers produced their own wheels. Instead they sourced them from either K-H, Budd, Motor Wheel Corp, or (later) Accuride. If you find numbers I can maybe find a reference for it. Stu