Ah, that is interesting. On the Coolermaster website they don't have a 500W Elite Power - so I guess the one in the case is a bit of a one-off. Anyway, the closest relative I can see is the
Elite Power 460W.
This PSU comes in two flavours, one has a voltage selection switch on the back (RS-460-PSAR-J3), the other doesn't (RS-460-PSAP-J3). The one that doesn't have the switch is limited to "Input Voltage: 220~240V".
Hence, If the 500W PSU that comes with the case has the selection switch - then it will be fine in the US, but if there is no switch - then it won't work in the US.