If you're checking for an installed component, then the best bet is to check the uninstall registry key.
On my machine the key value for "Microsoft SQL Server 2012 Management Objects (x64)" is this:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\{43A5C316-9521-49C3-B9B6-FCE5E1005DF0}
There may be a different key entry for the 32bit version if you need that, but this is the way I always did software install checks when I was an SCCM admin.
EDIT: As it seems that Microsoft change the uninstall key every version making it difficult to keep track of the installation this way, there is another key here which is probably a good one to check:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Microsoft SQL Server\SharedManagementObjects\CurrentVersion
You could check the value of this to see if it's greater than 11 and if not (or it doesn't exist) do your install.