Hello,
Short answer- no. However, WGIC installed on client machines does allow other features of WinGate to be used, such as restricting by application name those programs that can gain internet access.
I have successfully set up WG on server, and using the default settings, clients have accessed internet immediately without the need to install any client software. The help files included with WG and the Support Knowledge base
http://support.qbik.com/index.php?_a=knowledgebase are both very good resources that you should look at.
Hope that helps.