This is VERY easy to diagnose. Get an electric drill and the Mopar priming tool and hand prime it with the drill. If it has very little or no oil pressure, you will feel little to no resistance against the drill. If it slows the drill down dramatically, the gauge is
W R O N G.
"I" would also remove the gauge fitting from the block while priming it. If the oil pressure is as low as you describe, you will get very little out of that gallery.
