I may be off base, but to me it reads like sometimes Lee and Dan aren't addressing quite the same thing. My impression:

Dan: After fully machining the bolt and action, if the set up was correct then the bolt lugs should evenly contact the lug seats in the receiver. No lapping required.

Lee: On a basic rebarrel job where squaring the face of the receiver is to be the extent of the machining as long as nothing else is way out, a bit of lapping can improve the mating of bolt lugs and lug seats in the receiver.