Hi,
Thank you for posting in Symantec community.
Restart is not required & policies work as per the below note.
If the client software runs in user mode, the client computer gets the policies from the group of which the user is a member. If the client software runs in computer mode, the client computer gets the policies from the group of which the computer is a member. Many organizations configure a majority of clients in computer mode. Based on your network environment, you might want to configure a few clients with special requirements as users.
You set up clients as users or computers by adding the users and computers to an existing group. After a user or a computer is added to a group, it assumes the policies that were assigned to the group.
Refer this article to learn more about it:
http://www.symantec.com/docs/HOWTO27008