The oil pump is driven by engine rpm. Generally you want to see at least 15-20psi at a hot, low idle rpm and an increase of 10psi per 1000rpm. Pressure varies with oil temperature, cold oil is thick so it will have a higher pressure until it warms up and thins out. So at a cold idle you can get 70psi of pressure. The factory oil pressure gauges are nothing close to accurate. Put on an aftermarket mechanical oil pressure gauge and you get a totally different story. I wouldn't worry about it too much, the factory oil pressure gauges in these jeeps don't seem to be the most reliable thing out there by and stretch of the imagination. If your oil pressure needle was all the way to the right at the maximum full position, that usually means your oil pressure sender is shot or you have a connection issue.