Faulty Alarmstat/high temp sensor?

[Tenor]

I think I have this diagnosed properly, but here's the story.  I was running the bus to air it up and check for an oil leak at the oil pressure gauge - maybe idling for 10 min and it shut down via the engine shutdown air valve.  Found out that the rear of the 2 alarmstats is shutting down the engine.  The forward of the two is not.  I checked the function of the forward alarmstat by grounding and it works properly and shuts down the bus.  I got out the IR gun, and that housing is about 115 degrees, and the rear alarmstat about 110.  The forward alarmstat reads the same.

Those are the details, here are the questions
1.  Is there any separation of the two alarmstats inside the housing to cause one to run and the other not to?
2.  Any problem with using the forward alarmstat only, with both wires to the alarm and buzzer?
3.  Do these temp readings seem out of line?

Thanks!

Glenn