Maybe. WWoO is the first in a long series, and I admit it moves kinda slow, but the sequels are charming examples of 1900s-10s literature. Anyway, there are a couple of scenes from the book that made an impression on me.
It was never shown, in the movie, how they got back to the Emerald City from the WWotW’s lair, but in the book, the flying monkeys, who were no longer the witch’s slaves, carried Dorothy and pals most of the way. En route, the leader tells her a bit of their history. Originally, they had lived in Glinda’s territory, but didn’t belong to anyone. Glinda was engaged to the finest, handsomest, bravest, most noble and so on guy in all of Oz. In other words, a perfect target. The monkeys decided to play a joke on him the morning of the wedding, and grabbed him up and threw him into a river. He was perfectly okay, but Glinda was furious anyway, because no one messes with her man! As a punishment, she put them under a spell to keep them from jerking anyone around again. Eventually, of course, the West Witch subverted the spell; another slap against Glinda.
The real Wizard was seen by the four travelers individually, and always in a different form. The disembodied head was one of those, and the most cinematic, so that’s what ended up in the film. Anyway, he gave basically the same speeches about brains and love and courage coming from within, but to placate them, he filled Scarecrow’s head with bran and pins ("Bran-new brains!), installed a plush heart in the Woodman’s chest, and gave the Lion something nasty to drink “so you will have courage inside you”. When they had left, he thought, “It’s so easy to fool people who want to be fooled…but how can I make Dorothy think she’s back in Kansas?” Bit of John Edwards there.
Also, I’ll have to hit the library and look at some of the sequels, but I seem to remember Dorothy being a blonde pixie, not a wholesome pigtailed brunette. I can picture her thus in the original illustrations, which were exquisite, and I think I heard her described as blonde at least once.