I could be wrong here, but I'm assuming that all full size iPads will report themselves as 768 x 1024, no matter what their actual resolution—just as iPhones 4S and under all report the same dimensions, despite the later ones having a higher resolution.
That's also my take but I won't know unless someone else looks in their analytics and tells me they see the same thing.
An full size ipad doesn't really need a responsive design, although it's nice to have a responsive site for portrait view. If a lot of my ipad visitors end up being on a Mini, it's justifies a responsive site all the more.
I've visited my own site quite a few times using my wife's iPad Mini, but it doesn't show up in Analytics at all—although there is one row (the third, under iPhone and iPad) that says "(not set)" where a device name should be, so I don't know what that means—but it could well be the Mini. All iPad results just fall under iPad for me, though—there are no version numbers.