Please take a look at this article
explaining how you can check the SItefinity version of a page.
Although we base our sites on Sitefinity, we use custom build versions, and the http://www.sitefinity.com/devnet/forums.aspx
page uses a custom implementation for the Forums, not the Sitefinity 3.x built-in one. The custom forums implementation that we have is really complex and we do not distribute it.
I hope this information helps. Please do not hesitate to contact me if you need any additional information.
the Telerik team