But be careful - that info only tells you the software version of the server you are logged in to, in most cases, the controlling server(s). If you have other sites, in ESS or LSP configs, you should check each site, because they could be on different releases.
We have four sites, the main site has two controlling S8710s, two sites have S8710s in ESS configs, and one site has a S8300 with LSP config. Two of the sites are on 3.0.1, two are on 3.1.1, so different DST patches are needed. (Plus the S8300 is on 3.1.1, and is in Canada, so it has to be upgraded to 3.1.2. The other 3.1.1 is in the US, so it does not have to be patched.) Make sense? Yeah, it doesn't make sense to me either.
To be safe, if you have multiple sites, follow rgtrgt's line of thought and log into each site and look at it from the shell, or from the management web interface...