Dale,

Yes the thermostat must be under that polygon housing. Here's the stock engine, before modification.
Thermostat Housing.jpg
I'm still puzzled by IR readings being so much cooler than these sensors. The sensors are all upstream of the thermostat. In other words, they won't have water flowing across then until the thermostat opens. That too is puzzling. So, although I said that's were the thermostat should be, I have to wonder if it's elsewhere. Temperature sensors should be on the engine side of the thermostat, not the radiator side.

Have you called Power Tech and asked them?