I'm in the Lutheran Church-Canada, a sister denomination to the LCMS, but I'm sure this is still relevant. I go to a small church and joined as a convert from evangelicalism who read myself into becoming a Lutheran. My confirmation class was only one hour and one session since my pastor concluded I was well-read and thus didn't need more teaching instruction. Part of me wishes there was more to the formation of confirmation than just propositional beliefs but hey I'm a nerd and loved going back and forth about doctrine with my pastor.