Ideas On How I Can Determine If TPMS Actually was Reinstalled?

[jikhead]

Hey guys, I got some new Michelin Super Pilot Sports installed a few months ago. Installing and resetting the tpms were part of the package at no cost, but wondered if they really installed them. Even though the stock tires rarely got under pressure, the car always did let me know when they did. I have yet to see any warning light, and today checked them and they are 31 psi all the way around. The door panel says 35 psi.

Does anyone know the threshold limits that set the warning light off? That way, I can at least try lowering or raising the pressure to see if it sets the warning light off, if the tpms are installed. If anyone also has any other ideas on how I can determine if the tpms are there or not, let me know.