I don't believe so. As long as none of the thermal compound have been removed, it should be ok. Usually, people don't remove the heatsinks off of their CPUs unless they are replacing it or dropping in a new CPU. At that time, they always apply new thermal paste or grease. When you do that, make sure you get all the old thermal material off of the CPU and heatsink. A good, lint-less way to clean the CPU die is to put on a clean disposable vinyl glove, wet the end of your index finger with degreaser-wash or rubbing alcohol, and gently apply it to the surface of the CPU or die.
*Fact: Microsoft Window's Blue Screen of Death vs Computerforums.org's White Screen of Death. Which is worse?