I have heard that some scholars who've seriously studied the life and works of Frank L. Baum think that it really is a metaphor for the arguments about the gold standard that were raging in his day. There's something about the Yellow Brick Road representing the Gold Standard and the Emerald City some other form of currency, I don't care about the details myself, but I'm sure a quick google search will tell you everything a sane person might want to know about it. And whether the Freemasons were part of Baum's deal.
As for the movie, I'm pretty sure the gay context was unintentional, strong through it is. Friends of Dorothy! Freudian subtext might have been intentional, Freud and psychoanalysis were all the rage during that period.
A friend of mine has been pushing that book on me. I intend to read it. Maybe I'll give a book report here after, lol. But anyhow, yeah, the gold standard seems to be the real deal when it comes to author's intent. Kinda obvious when you think about Oz. oz =ounce ...
The book is very, VERY short. Reading it is comparatively painless.