It looks like it's basically a tour of the public areas of the theater. You might be better off checking to see if there's anything you want to see at the theater than night and just buying a ticket. It can be kind of cool to stand in a nearly empty theater if you've never done it, but not sure it's worth $20 for only 30 minutes total. You can also go to the Dolby review on Yelp and search for reviews that contain "tour." There are some recent negative reviews. It's kind of hard for me to say it's worth it, but I've been to the theater many times and also worked on several events there and seen all the backstage areas, and even been there when the Oscar stage was still up. I think if I were going to take a theater tour I'd want to see more backstage areas that aren't on TV, but I'm coming at it from a different perspective.
You might also want to check to see if there's a red carpet premiere at the Chinese Theater that same day too. I think most people would find a few minutes of that more interesting than the Dolby Theater itself.