Because you'll be in the MK during the day, you might want to have lunch at BOG if you can't get a dinner reservation. It's counter service so no reservations accepted. You'll have to line up on the bridge, but the wait isn't too bad. If you're mainly interested in seeing the interior of the restaurant and soaking up the atmosphere lunch might be a good choice.
Differences/similarities between lunch and dinner:
-You'll be able to explore all the rooms at either meal and often at lunch you'll be able to choose your own table. At dinner the CM will seat you.
-Menus have some differences: entrees (mains) are different, but desserts are identical. The 2 soups are on both menus, but dinner has additional appetizers (starters).
-Lunch is brought to your table in the carts used at dinner for the desserts. Lunch is served on real dishes and silverware. Drinks are in paper cups.
-Biggest differences: At dinner you can have a photo op with the Beast after you finish dining and beer and wine are available at dinner.