I'm getting some pretty awesome accuracy from 700's that only had the lugs lapped for better contact. Guess I'm siding with Clay Spencer on that point.
If I was going to use a 700 action for a benchrest rifle build, I would investigate all options, and select the ones that provide results. But, my rifles are hunting rifles and I figure that 3 shots at 100 yards giving 1/2" groups, or better in a few caes, is good enough.
In the overall scheme of things, I think there are other areas of the rifle/ammo system that are more important than bushing firing pins, as an example. GREAT triggers come to mind as being hugely important, and ammo with minimum runout...