For years before I got into OC'ing and up to the present, I have been an avid amateur gunsmith. Lapping was not a new term to me. However, lapping, as applied to OC'ing struck me as odd because in gunsmithing, with the exception of fire lapping a barrel, lapping implied taking the two mating components, putting lapping paste (grit in an oil carrier) on them and cycling them until the action was more smooth. Only in OC'ing have I seen the term lapping refer to putting a finish on only one half of the mating components.
That, having been said, I would never lap a Duron or Tbird core. They are fairly smooth to start with and AMD has put a sealer on it. Now, I don't figure that sealer is free, so I assume they do that for a reason.
By now, everyone is probably tired of the "letting the smoke out" metaphor/joke, so I won't go there. ;D
Hoot