No. Windows 2008 copies the entire media content to the installed server with all components placed in the Single Instance Storage folder (SIS), C:\Windows\winsxs. When a feature or role is installed on the server, the required files are either copied or linked from the SIS folder so no media is needed. When updates such as a service pack are applied, all components are updated so once again no media or copy of the service pack is needed to add additional components.