HVAC part identification

[Rockycmt]

I am sloowly rebuilding my furnace. 30+ years old. It has light use so not wanting to do a replacement. I have two swithces in the heat exchanged of the box. (Not the fire box) One is gray 471955437 and one is red. Cant fully read the numbers. Can anyone tell me what they do? I assume
one is a limit switch that will close when the temp goes up. To turn on the HVAC fan. And opens as it cools to turn the fan off. And the red is a high limit to shut down the whole system if too hot.

Thoughts?

 

[Fitter30]

Bottom probably a fan control n.o. 125° on 100° off. Pull one wire ohm it should be open
Top is the limit 175° opens 140°-145° closes pull one wire ohm it should be closed
Take a pic of the wiring diagram inside blower door.