When Apple replaces your iphone, is the new one really a used one?

I recently got my iphone 5 replaced, and when the guy was getting the new one he just took one out of a plain white box. I'm just wonderingly if that iphone was used before and went through a whole process to be fixed and restored to looking brand new.

I asked the guy who replaced my iPhone 5 that question and he said it could be new or refurbished, but if it's refurbished it has a brand new screen, battery, back plate, everything. The only thing that might be reused is the processor or other "nonconsumable" parts.