I am pretty sure they are open. I think they would say if they had zippers. Also if you click on the pair of pillowcases and then enter the design tool there is one side that has more room on the end outside the green border and that is the side that is open. You don't want the main part of your design on that part and you will see that the open side is on the opposite side on the second pillow. Hope this makes sense and helps. Also when you choose the pair of pillowcases you will see both pillowcases shown side by side in the last two examples.
