Try to buy a lower running t-stat from a GM dealer and most parts departments will tell you that that don't recommend, sell, or use anything otgher than the OE 195, while charging way too much anyway.
I did notice that the bottom of, both, the Stant and the AC Delco were stamped STC, which stands for Standard Thomson Corporation - the division that makes t-stats for Stant (which they now own). So I guess I answered my own question.
The 180 is hard to pick up at Pep Boys or Straus Auto (Auto Zone has Robertshaw I believe but they seem to always be sold out) but NAPA always has the Stant SuperStat, although it'* almost the same price as the dealer offers. Even yunder $9 it'* well worth it for sure!