I don't know much about dog shows/expos and the like but I believe socialization also needs to happen on a daily basis in real life. We take Princess Sophie as many places as we can. She goes to the bank, to Wal-mart, to the DQ drive up, and she gets to interact with the people that are in those places. I am also taking her to a Yorkie meet-up later this month so she will be able to meet other yorkies and play with them. That's just what I feel socialization is really all about. Meeting new people and animals and learning that it can all be done safely (in your arms).
I can imagine a dog show/expo and the like could be considered socialization because she will be in a different situation with lots of other people and dogs around but I would caution if this is the only socialization she gets. I hope you have a great time at the show and your pup enjoys the excitement of the event. Please take picts and let us know how it goes.
Have fun!!