Oops, after reading your question more carefully, you have nothing to worry about. The European and American Wiring Standards both use pin 1 for ground. As long as pin 2 connects to pin 2 and pin 3 to pin 3 at both ends of the cable, your XLR interconnect cannot distinguish itself as either American or European standard. As long as the input and output on the equipment follow the same standard, ANY correctly wired XLR cable will work as intended.