Unless its stated that they used 'select' or binned chips , there is no difference. No special testing. Same with ATI and Nvidia. Now I've read , Gigabyte binned gpu's for a couple of their models before. One was a 5870 and another was a GTX 260. But the average 3% o/c in the models mentioned no.
superclocked is for lazy people that dont have the know.
You get HIGH gpu power increase for MINIMAL effort (overclocking part), but with a HIGH price tag.
My opinion is to get a regular GTX 480 get a guide ( there are MANY around), take your time read it CAREFULLY an you will easily achieve your superclock specs or even higher for significantly less money.