From reading LPM and Aviation Consumer, and from stories much like
yours, the probability of a cylinder arriving from Lyc or Cont. (or
even ECI) and being completely within spec is about zero. It is just
assumed that any shop worth their pay will have to lap a valve or to,
maybe put the rings back on in the correct order and direction, etc.
It's very sad, but it's a limited supply chain and that's what we get
for our hard earned money. And yes, it should NOT be that way.

From everything I can tell, Superior has their act MUCH better
together, and eventually it will show. The problem for now is, as you
have observed, is that Superior still does not make a lot of cylinders
(such as for my TSIO-360-FB).

BTW, back when GAMI was getting started, they needed to show a quality
control comparison to the Continental injectors - so they ordered a big
bunch (in the three sizes) direct from Cont. Not only did it turn out
that TCM's spec for tolerance on those injectors is ridiculously wide,
but half of them didn't even meet THAT spec. Think about it -- a
company making the engine that keeps your ASEL in flight, and they
can't even drill a hole the correct size in a metal rod.