First sign of MacBook Pro Graphics Failure?

Now that I’ve got my laptop back, and it’s all working fine, it occurred to me that for some time (maybe forever?) I had been getting a 0°C temperature reading when trying to see the temperature of the graphics related sensors.

I fired up TemperatureMonitor, and sure enough, it’s now got values in there.

I suspect this is the first sign that the graphics chip is on it’s way out.