Well these handy dsquery commands will make it easier:
For Active Directory Schema version
"dsquery * cn=schema,cn=configuration,dc=<< your domainname here>>,dc=local -scope base -attr objectVersion"
For Exchange Schema version
"dsquery * CN=ms-Exch-Schema-Version-Pt,cn=schema,cn=configuration,dc=<
Reference the results for the above dsquery commandlets to the following lists below:
Schema version for operating system
13 - Windows 2000 Server
30 - Windows Server 2003 RTM, Windows 2003 With Service Pack 1, Windows 2003 With Service Pack 2
31 -Windows Server 2003 R2
44 - Windows Server 2008 RTM
47 - Windows Server 2008 R2
Schema version for Exchange application
4397 -Exchange Server 2000 RTM
4406 -Exchange Server 2000 With Service Pack 3
6870 -Exchange Server 2003 RTM
6936 - Exchange Server 2003 With Service Pack 3
10628 - Exchange Server 2007
11116 - Exchange 2007 With Service Pack 1
14726 - Exchange 2010 With Service Pack 1