Exchange 2013 Upgrade Code

Hi, 

I am looking at using function “MsiEnumRelatedProducts” to verify if Exchange 2013 is installed on the machine.

To use this function we need Exchange 2013’s upgrade and product code GUID’s.

Question 1: Does anyone know what GUIDs we should use for this? If upgrade code is needed, where can I find it?

Question 2: Is this a standard way to find out if a particular product/version is installed on the system?