Is the problem with the gauge or the oil pump?
According to the dashboard gauge, engine oil pressure in my 1951 Willys F-head four runs 50+ psi at all times, even at hot idle. Everything is quiet but I suspect this cannot be good for the cam drive gear. Should I remove and inspect the pressure relief valve?
The oil gauges of that vintage automobile used copper tubing and direct pressure for the gauge. The copper tube goes from a fitting on the block to the back of the gauge. This setup is very reliable provided the copper tube is not bent or kinked. If it gets kinked, the oil in it may be compressed and is stuck there. Check the tubing for kinks or bends. If the tubing is straight and unblemished, remove it and clean it out to make sure it is not blocked with dirt. If it is kinked, replace it.
Once you have the tubing loose, the gauge should read zero. If it doesn’t it will need to be rebuilt or replaced. Cheap electronic oil pressure gauges are available from auto parts stores, and you can hook one of them up and verify your oil pressure easily enough. If the new gauge reads high too, you may be correct as regards the oil pump.
It would be quite unusual for the pressure regulator on the oil pump to be faulty or out of adjustment on a seasoned engine, but not impossible. I am not sure if the oil pump is external on that engine or not. If it is external, you can clean and adjust it so it will work properly without too much trouble. Otherwise you may have to pull the pan to get at it, and in that case you would want to clean the pickup basket and the pan. You can also assess whether there is a buildup of sludge in the engine that could be causing you problems.