I just taught rifle merit badge this week. I brought up a slug of .22's (Kimber 82 G's and Remington 40-X HB's) as well as a T/C Hawken 50, a Douglas 42" barreled 40 cal flinter, a Knight in-line 50, and an 1863 Sharps carbine breech loading muzzle loader.
Most of the kids needed trigger time. While the muzzle loaders were a lot of fun for the kids to shoot, and go through the experience, the act of shooting, (sight picture, sight alignment, trigger control, breath control) was what they needed more time on and experience in sending rounds down range. For that, the peep sighted target guns taught them plenty, and in a hurry. With the muzzle loaders, the kids could only get 1 shot off in the time it took for the .22 shooters to get off 5. Plus, the target .22's had adjustable sights. The muzzle loaders don't.
I'd say bring them both, and have them qualify with the standard .22's. THEN move them in to the smoke pole. Because of the increased boom, smoke, and particularly slow lock time and pan flash with the flinter, most of the kids didn't shoot the smokepoles as well as they did the other guns. Your mileage may vary, but that was my experience.