Install questions

1) after an install of the Spokes software (downloaded from Plantronics | Support | Downloads & Apps | Plantronics) I notice there are two PURE.xml files installed (see command-prompt output below):

C:\>dir pure.xml /s/b
C:\ProgramData\Plantronics\PlantronicsURE\PURE.xml
C:\Users\All Users\Plantronics\PlantronicsURE\PURE.xml

Is the inclusion of the PURE.xml in the All Users profile a deliberate action? Should I be updating both files to point to my plug-in assembly?

2) is there a "proper" way to determine that Spokes has been installed as a prerequisite to running my plug-in's installation? Right now I am checking for the presence of the following registry key to insure that Spokes is installed:

HKEY_CLASSES_ROOT\CLSID\{F9E7AE8D-31E2-4968-BA53-3CC5E5A3100A}

If this is not a proper approach please advise...

Thanks.