If you are talking to a benchrest shooter, about the fit bolt in his 6XC, shooting carefully assembled hand loads - soft seated(final seating is done when the bolt closes the bullet against the lands), when fired from a vise bolted to a bench, it matters. Consistancy of chambering a round in a bolt gun is one thing, an autoloader is another. That fit bolt will lock up the same evertime a round is chambered.
An auto loader isnt even in the same ballpark. A bolt fit to minimum headspace will lock up more consistantly. But you are splitting a hair so fine, you would never know it (unless you were backing out primers because the headspace was so far off). Auto loaders have too many things going against them. No repeatability of chambering, bullet setback, bullet jump, shifting of recipricating weight, magazine feed, the little variables are too many to add that it would ever matter, or you would ever notice.
Buy a set of head space gauges for your AR, then get a few differnt bolts that all "pass". Swap those bolts in with your "fitted" bolt and you will never see any difference in accuracy.
BTW - All the production WOA barrels shipped with a bag of bolts, actually come from Frank White at CLE. Do a search of range reports on any of those barrels, if you want to know how they shoot.