You can absolutely copy an existing event in Tickets!
You have the option to do this when creating a new event! After creating your event in Tripleseat and then clicking the 'Open Tickets' button to open the event in the Tickets dashboard, you will see the option to ‘copy data from an existing event’ on that first 'Create a New Event' page on the 'Preferences' tab (see screenshot below).
From the Preferences tab, check the box next to 'Copy Data From an Existing Event?' and then choose the event to copy from. You can even select only specific parts of an event to copy (ie: Registration Forms, Email and Mobile Content, etc), in case you want to select some parts but not others.