If it's just in the simulator then surely all the details she finds about the ship are from the simulator and are constructed for the purpose of the test.
Not "surely," just possibly. There's no reason a simulator couldn't use a real ship, in the same way that, say, flight simulators use recreations of real cities and airports rather than making up imaginary ones. My point was simply that the presence of data on the Kobayashi Maru in the simulator didn't prove it was real. But it doesn't prove it wasn't real either. It doesn't prove anything.