In FC2 T3, it seems that system-config-mouse does not install .desktop file - at least, such a file was definitely not installed on my system (clean istall). As a result, this tool does not show in the menus.
I removed the .desktop file intentionally because it is not really used often enough to justify a placement in the menu. The main use for system-config-mouse is in anaconda and firstboot reconfig mode.
Granted, it is not used frequently - but sometimes one does have to use it (e.g., when replacing a mouse). There should be some way of doing it for those who do not know that they should type system-config-mouse. Maybe hiding it in a submenu. Releasing a system in which user cannot easily do so basic a thing as replacing a mouse seems broken to me. By the way, same argument (...not used often enough) can be made about a lot of other config tools - one does not use, e.g., kickstart configurator or system-config-services every day, yet we have left them in the menu.