However, I think Apoc 13:16 also might refer to the past and the fact that Potelmy 1st (217 b.c.) branded Jews with the stamp of Dionysos. (Not all of them, just those that submitted to him)
Circumcision was another way to keep track of the Jews. It was probably a litte embarassng asking for their ID though.
Seriously, considering the lack of technology in those days, circumcision was the 'chip' of the early days. Was it used to buy and sell?