In webadmin it used to be under installation but I don't see it there anymore...
...maybe I was thinking of somewhere else, but I don't think so.
Anyway you can always go into webadmin > advanced > software > Software versions and with "Core" selected as which computer? scroll down to the LMCE packages and you should see the build date.
It will be something like X.X.X.XX.14032328853 meaning - I believe - 2014 Mar. 23 28853 build.