I thought Coot was asking more about the information specific to the ISS, on how to get to it and dock, etc., not orbital mechanics in general.
I'm sure someone could observe the station and figure that out, but it would probably be safer if they just got that data from NASA.
Getting to the ISS is all about orbital mechanics and rendezvous & docking techniques. And the ISS's orbit isn't top secret, you can get very detailed info on it's orbit at any given moment on the internet. But of course since SpaceX is being hired by NASA
to make this flight they won't have to resort to Googling the ISS orbital info.
In any case, if Coot was asking how SpaceX would know how to find ISS then the answer is NASA will give them all the data needed.
If he was asking how SpaceX figured out this "getting into orbit and rendezvous/docking stuff", the answer is it isn't top secret NASA only knowledge.