Well, it could have readings in psi, bar, kg/cm2, lpm, or something else. Make sure you're reading psi (or possibly "lb/in2"). The gauge closest to the inlet (if the inlet is on the side) will be the high pressure gauge. It's possible the gauge is blown, or it might just be "off" by 5 units of whatever units you're reading.
I'd say hook it up and see what happens.
Or, if you want, you could return the reg without testing and try to get one that has accurate gauges.