If you are using the demo cirrus website the product details within the tab are pulled from the objects. Have you connected the data repeaters that pull data for the product details to your objects? If you don't have access to the objects or haven't connected it to the appropriate objects the data wont show up
You need to check that product need to be visible to guess user also ? If yes make sure the access is given... and the controller and Vf page need to be accessible by guest user ...
Thanks