Even as a teenager in the seventies, I thought the Tin Man in the original movie was supposed to be gay. Like "not having a heart," meant unable to love as he pleased due to the stigma. Plus he just seems gay. I suppose you could make something of the fact that the first thing he asked for was lube.
There was a lot of symbolism of the politics of the time the novel was written (1910). Dorothy's shoes were silver in the book, to represent the policy of bimetalism, a silver and gold standard rather than a pure gold standard. The Cowardly Lion represented William Jennings Bryan, the most prominent advocate of that who made the famous "cross of gold" speech. The Yellow Brick Road represented gold as the illusory path to success, while Dorothy's silver shoes saved the day.
I'd settle for a jack in the box taco standard for the dollar over this "fiat money," we use now.