According to these responses at social.msdn, yes, in theory.
In practice it also depends on how many and what components the older install had. The uninstall script can run into some nasty bumps if it at all attempts to, and possibly succeeds in closing a service used by another existing VS install. Shouldn't, though.
Take Git, for example. I don't use it- but follow the advice at this thread by removing Git components from within the old IDE before uninstalling it. In fact it's strongly recommended to remove as many addons/extensions from within the IDE to be uninstalled, as possible, first, and then remove the appropriate VS service packs. Components like Crystal Reports are nicely handled by the IDE (in this case VS2010) uninstall process.
Fun Fact: The VS2010 SP1 uninstall actually requested the mounting of the VS2010 DVD, whereas the IDE uninstall did not!
Another (Plan B) method is to flick through Apps & Features in Windows Settings and search for anything Visual Studio related beginning with "Microsoft". If, when removing Microsoft program A that you know is associated with the IDE being uninstalled, the uninstall hangs at 0% because of a TSR or service that can't be closed, then search for a similar program matching A and uninstall that. The approximate install/modification dates of the IDE are clearly indicated, but bear in mind that major Windows revision upgrades can also change the dates of some components to the date of the upgrade.
Plan B can be very time consuming and error prone, and applied only as a last resort.