With a few exceptions, no, it is not. If you have at least 3000 reputation, you should vote to close. We want the community to be involved in moderating the site. See How should my flagging change when I gain the ability to vote to close?
From http://superuser.com/privileges/close-questions:
Note that once you gain the reputation to vote to close, you should no longer flag for moderator attention to have questions closed or migrated. It is your responsibility to vote now.