just make sure that when you adjust the regulator to the lowest setting, you can easily adjust it for low numbers (ex: when you start to add pressure, the low pressure gauge doesn't automatically spike to 25 psi, and you can bring it down lower). If that were the case, and you put on a lower rated gauge, you may ruin the gauge by over-pressuring.
Even so, you still risk over-pressuring a lower rated gauge if you put one on. I would suggest that you do swap it out, but put a pressure release valve that opens at 60 psi, so you don't accidentally over pressurize the gauge.
I would assume the regulator is able to get to 150 psi or so. Kegs are rated at 130 psi I think, so a pressure release valve would be very necessary.
There's also the chance that the gauge was already swapped out, and the regulator can't reach as high of a pressure as the gauge says. Try hooking it up and seeing what the max pressure really is.