IMHO, I think Samsung did it mostly so they can see what they are coming out with to COPY it as well.
Samsung's argument is that they need to see it in an attempt to prove that Apple's alleged trade dress is not consistent (e.g. changes in next gen products) to the point where not having it would substantially weaken their legal ability to defend themselves.
Considering Apple hasn't announced the existence of such products and the argument is over present alleged "Apple trade dress", the argument is flimsy at best.
Samsung would also not have direct access (basically, legal industrial espionage). 3rd party lawyers would handle it and make a summary.