They have games you probably never saw in arcades, too, because they didn't see wide distribution. For example, a previous boss of mine used to work for Midway back in the day, and he donated some of the arcade games he worked on to Galloping Ghost. Galloping Ghost helped him restore one of his rarest ones, too, and it's playable there.
More on topic, if you're in the area to check out Galloping Ghost, you can head a little ways Northwest to Schaumburg and go to the 257 restaurant, which is basically a Namco museum and has food, bowling, and a bunch of Namco arcade games and memorabilia.
I would not recommend going to 257 with the intention of having a good time playing arcade games. Their selection is fairly limited. As the name implies, it's good if you just want Pac-Man games, and mediocre for much else.
It's definitely not on the level of Galloping Ghost, for sure. It's more of a place you go to if you want to do a mixture of bowling, food, and (Namco) games.
More on topic, if you're in the area to check out Galloping Ghost, you can head a little ways Northwest to Schaumburg and go to the 257 restaurant, which is basically a Namco museum and has food, bowling, and a bunch of Namco arcade games and memorabilia.