I say it is a blooper by the PO. You have no sensor or pcb to drive the overtemp alarm. And only time oil pressure/temp alarms comes on is while cranking. He has wired it so he knows when he was pushing the button. OP alarm should come on while key is on and OP switch is grounded. Your OT alarm is non-functional unless you buy the very expensive t-stat housing with dual sensor bungs and a OT switch and run the wires.
You can get functional OP alarm by using one of the diagrams I posted.
Test you OP alarm with the engine running ground the wire at the OP switch.
Les
But it's not a previous owner setup. It matches the Catalina wiring diagram.
It's not intended as an over temp setup. Unless there's some electronic magic I don't see.
It's a secondary buzzer and light, activated only when the start button is pressed.
The oil alarm and light are separate and wired conventionally.
