2006 Kia Optima Ball joints

I was told by a mechanic (he was performing an alignment) that my front upper ball joints needed to be replaced. My car is still covered under warranty so I contacted a Kia dealership. The mechanic at the dealership told me that I do not even have upper ball joints on my car; that I have struts instead. Is this possible? I am trying to resolve this dispute so that I can fix the problem if there is one.