The default setting for showing schedules to clients only affects future projects that you add.
To check or change the setting for an existing project, go to the main menu, click on the "Projects" tab, and then click "Edit Projects." Find the project in question and click the "Edit project info" link. If scheduling is enabled for that project, you will see the option for changing whether the clients can see the Published Schedule.
If the clients can see the Published Schedule, they will only be able to see the calendar view, which includes the task name and percent completion.
If the clients cannot see the Published Schedule, they will still see a list of the milestone names from your Published Schedule, with checkmarks next to any that are 100% complete. However, the clients will not see any dates on these milestones.