From what I understand, the earlier sensors will turn off the light but won't provide (or perhaps not provide accurately) the tire pressure in real time.
I have sensors for a 2010-2014 Mustang on my 2015 Mustang. Not only does the light not come on, but the Tire Pressure is reported and is accurate. I was curious about the reporting as well and was manually checking pressure before and after driving to see if the match was the dash readout was.
Something many people don't know is that you actually have to drive your car to get the sensors to report information. When I start my car, the pressure readout is from when I previously stopped driving the car, an before getting out of my neighborhood, the new and cold pressures are reported.