Agreed, the IHS (Integrated Heat Spreader) is epoxied to the cores so removal will damage the cpu.
Lapping the CPU IHS will Void Your Warranty!!! Which is why I don't recommend Lapping it to most Users.
Lapping the CPU IHS is easier than lapping your heatsink but it is not a substitute for lapping your heatsink. I'd say 95%+ (guesstimation) of all the cpu's on the market don't need the IHS lapped. I rarely lap the CPU IHS. At best it may drop my average temp by a degree or 2, what I'm hoping for is that it will group my core temps closer together. As in, for example, 38-40-39-42 going to 38-39-38-39.
I said lapping the CPU IHS was easier than lapping the heatsink, it is, but it's also more delicate. The IHS is thin and it shouldn't need very much removed. Remember, Patience is a Virtue. While you might start with 400 or 600 grit sandpaper when lapping your heatsink, I started with 1000 grit sandpaper on this cpu. I wouldn't recommend starting with anything less than 800 grit. I switched to 1500 grit when it was about 60-70% flat and smooth. When the IHS finish is removed and its copper is fully exposed I switched to 2000 grit paper until I could see myself good enough to shave
Edit: I've got my tracking # with a Friday delivery. I should be fast again by Saturday