I was also told on my recent trip to Disneyland about an interesting fact regarding the castle. Court, the conductor of the Train told me that the top half of the castle is actually on backwards. When Walt Disney was undergoing the final plans for building Disneyland a few of the guys decided to mess around and see if Walt would notice if they turned the castle around on the model. Well he didn't, on the day he signed the final plans it was very busy and he walked in signed the papers and walked out without even looking. OOPS! Below I have circled the top half of the castle which should have actually been turned around facing the Carousel. These are really the windows to the castle bedrooms.
In this famous picture Walt himself is walking threw the Castle realizing the mistake!