Camero oil pressure gauge

My daughter has an eighties vintage Camero.  The oil pressure light is
staying on, but she says the car also has a gauge, and the gauge is
showing reasonable pressure.  We are surprised that it has both.  She
thinks maybe the light is for an oil level sensor but I doubt this-
those are usually pretty pricey and on luxury cars.

We are also trying to figure out if the pressure gauge is mechanical
or electrical.  The engine is mostly buried under the cowl and
firewall and the bottom of the dash is not easy to see under.  Anyone
know if that gauge is mechanical or not?