Last week Tarek Majdalani, a Microsoft Most Valuable Professional, posted an article about identifying which version of TMG 2010 is installed – RTM, Service Pack 1 or Update 1 to Service Pack 1.

The article is available on the TechNet Wiki site here.

If you are wondering what version you have installed on your server, this article has all the information you need.

TMG 2010 Level   TMG 2010 RTM

TMG 2010 with SP1

TMG 2010 With SP1 & SU1
Version From 
Help Menu   7.0.7734.100 7.0.8108.200

7.0.9027.400

http://social.technet.microsoft.com/wiki/contents/articles/how-to-determine-which-version-of-tmg-server-2010-is-installed.aspx