No, they have CMs who pass out the candy. They have big containers they grab from and the assortment in them varies. There are various locations throughout the park that have a big Goofy Candy Company balloon, these are the trick or treat locations.
I am a peanut M&M fanatic and there were a few cast members who were nice enough to pluck through and grab those for me. Some are not as nice, since there is a line, especially at the start.