USB 2.0 H/W requirements?

I have a USB 2.0 capable mobo and am adding ports to my headers. I was wondering if there is a difference in the actual HARDWARE between USB 1 and 2? IOW, if I install some USB ports into the back of my machine (via factory-supplied headers)will the”plugs” support both versions, or is there any difference? (They have no markings on them). Looked around online for awhile and couldn’t find much. Thanks…