Want to write script to determine if SEP 11/12 is installed on remote system

I would like to write script to determine if SEP (11 OR 12) is installed on a remote system (i.e. 32bit, 64bit, Windows XP, 7, 2003, 2008, etc)

So far I found this, https://www-secure.symantec.com/connect/downloads/batch-script-check-and-install-application-package, but I cannot find the product key that corresponds to various versions of SEP.

When I go to the registry of my workstation, I cannot find HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Microsoft\Windows\CurrentVersion\Uninstall\{4ECF4BDC-8387-329A-ABE9-CF5798F84BB2}
even though SEP 12 is installed on my workstation

Or, is there a path and executable to search for that is common to both SEP 11 and SEP 12 regardless of hardware platform and operating system?