As Colin says that is correct. I do want to add that you do need to set a password as well but that can be anything you want.
If you have multiple machines then you can set workernames by adding something to the username like this:
38HRDQeecdfQnCyrnLEtKJGnEsrLG3XUCt.worker1
38HRDQeecdfQnCyrnLEtKJGnEsrLG3XUCt.worker2
etc
You don't need to do this but it is handy if you want to monitor different machines and how well they are mining because with these extended usernames you can look up stats per worker on the ckpool site.