As far as I know, Gnome doesn't have an actual "control center", the thing that you're referring to is basically a program that collects the icons (shortcuts, links, ...) of the actual configuration tools in one window where it's easy to start them. The configuration tools, however, should reside in the system/admin menus by themselves also, so you can launch the preferred configuration from there. Gnome does not have a control center similar to that of KDE, for example, where there is a single program to hold most of the configuration options (Gnome has a window to launch the various configuration tools to configure the specific options).
Having said that, it is possible that RH has their "own" tool to do that. Ubuntu has a "control center" which I don't think is in the Gnome release, but is written by the Ubuntu team. I'm not 100% sure about that but guess so..like RedHat distributions have those RH-only configuration tools that are not found in other distributions. So if there is another control center than that Gnome's default one, which is more like a folder with the config program links inside, it's done by RH in your case and should not be named gnome-control-center, but something more RH-specific.
So, to conclude: no, I haven't seen a wm choosing option either, and Gnome's own "control center" is not a control center in the sense of KDE (it's more like Windows' Control Center, which is also a folder with links to various tools). Never seen anything on the web that says you can switch WM from inside Gnome's configuration tools, but if such a thing is possible, it's most definitely a RedHat-specific solution. So if you've bought RHEL from them (it's not cost-free, isn't it?), you should be free to ask them about this - they know if it's possible.