Is the registry tree structure for SOFTWARE\Microsoft\Internet Explorer\MAIN\FeatureControl\FEATURE_BROWSER_EMULATION automatically created when IE is installed?
Yes, the registry entry is included as part of IE installation.
It was first introduced back in IE8 as part of an extensibility improvement:
http://blogs.msdn.com/b/ie/archive/2009/03/10/more-ie8-extensibility-improvements.aspx