Had problems in the past in order to install Outlook side by side versions on the same PC?, so no it's gone!. When you install Office 2013 from the web, you may install the full packaged including Outlook 2013.
One of the limitations of side by side installations of Office in the same Machine was that Outlook only could be installed once for the version you choose. Now Office 2010 and Office 2013 can be installed with full features, Outlook 2013 will assume you definitions from 2010 COOL!
Of course you can't start both at same time!