I assumed based on Alan's response that was a thing of the past, and given modern manufacturing of higher quality rings, etc that may not be necessary.
So which is it? With quality components is there improvement to be made by lapping rings, etc.
I see Nate says but is doing no harm mean actually doing any good?
Its opinion so there is no "which is it"
In my experience with lapping, if its done correctly then the best case scenario is you do no harm, and no good. I see no point taking risk for no benefit.
That said, it depends on the components you use. There are still rings/bases on the market that do benefit from lapping. I just see no point in buying those rings and bases.