Yes, DY, you are correct. According to the folks at LS1Speed, from whom I bought the Hypertech Powerstat that won't fit on my car, that's exactly what they did... changed the housings in midproduction.
I had my stock tstat out of the car TWICE, so I know it well. It is stamped with 86*C. This converts to a little over 186*F, which confirms what 6M GTO said.
My temp gauge seems to go from "off" to "on" (mid-range) and nothing else. Barely a wiggle, regardless fans running or not. I will use the DIC to test my new tstat, if I can ever get one. (I was going to get a 180* tstat, but since our stock tstat is 186*, that would be a waste. Might as well get the 160* tstat.)
My "stock_tune" fan temps were as follows:
Fans Stage 1 - On 226, Off 219
Fans Stage 2 - On 235, Off 226