Marx made a brass (or copper) looking work train headed up by a brass Canadian Pacific engine and tender. It featured a brass searchlight car and the wires on the side dump were also plated brass. This caboose makes me think that they were also considering a brass caboose to go along with the set. It is regular production as far as the stamping and punching are concerned and it doesn't appear tampered with. As the picture below shows, the ends are regular production, red! I guess the brass body and cupola were enough for them to decide no!

(Courtesy of Roy Bendure)