What is the set of cards used in the Wisconsin/Berg Card Sorting task?
The 64 card version is just a shorter version, according to (Greve, 2001). Instead of running 128 total trials, there are only 64. The original test was developed and, crucially, normed for 128 trials. However, this version takes a long time to administer, and clinicians were interested in a shorter version. It was found that cutting the number of trials in half worked reasonably well. 

So the short answer seems to be that the decks are the same.