As I mentioned, you can search for some of this information. A first stop would be in the NWBC space of SCN: http://scn.sap.com/community/netweaver-business-client
This space covers the release information for NWBC 5.0
As part of SAPGUI 7.4 install, you have the option to install NWBC at the same time. If you are allowed to install for your desktop only, you could install it and have a look around?