I would expect this work to be done to the Special Combat Gov't Model, and the Gunsite models, but probably not on any of the regular production items. I consider them to not be so much essential, as something that's nice on a custom gun. Plenty of guns have worked perfectly, for decades, without such work. That said, the first thing I did to my '04 stainless M1991A1, before even shooting it, was to polish the breechface, barrel throat, extractor hook, adjust the extractor tension, etc. It makes the gun run smoother, and over the long haul, more reliably. I would expect all of Wilson's guns to have such work done to them, as part of their normal specifications.