Chris, Looks like some funny wiring has been done on your car which sadly is the norm after 45 years.
the SOBill Wiring diagram shows a red with black stripe wire going to the temperature sensor.
One of your photos shows a red with black stripe wire connected to your device but it has a non-factory terminal.
I also think I see a red with black stripe wire at the gauge.
I suggest you get a long jumper wire and test continuity to determine if the red with black stripe wire at both locations is in fact the same wire.
If you find that to be the case then follow my previous advice, buy the proper sensor, mount it where it belongs and attach the red with black stripe wire.
That could make your temperature gauge functional.
But I have no idea what you should do with the vacuum device shown in your photos