Out of curiosity, how many kids are in your class? Even if one of them has read The Giver recently, it's probably still worth doing, simply for the discussions the kids can have. The Giver is definitely a thinking book, and kids generally explore the themes and issues in books much deeper when they're discussing it in small groups.
For example, in my fifth grade class, we spend the month of January with Tuck Everlasting. One of my students read it last year (and shared some plot points with her friends last year as well.) Because of the way my co-teacher and I structured the unit, these students are thinking about the story in a different, deeper way. (We created literature response activities focusing on characterization, setting, figurative language, and other literary devices, and for each set of chapters, they break into small groups to discuss questions and concepts on the higher levels of Bloom's taxonomy.) Anyway, they definitely strive higher when they're required to justify their thinking to their peers.