It depends on how hot they are run. Most quotes for 50,000+ hours assume optimal cooling and under-voltage driven, bogus specs in real-life applications. Flashlights are good examples. Early Maglight conversions didn't have enough heat sink/transfer for the LED assembly and will not last that long. The LED turn signal assemblies I've seen in automobiles have a HUGE heat sink attached. I haven't had a chance to look at the newest auto LED headlight assemblies yet but I'm betting on some aggressive venting.
I assume these reading LED's are not as highly driven. Does the lowest part of the screen bezel get at all warm? If not then I wouldn't worry.