The engine looked pristine internally. Cam and tappets had minimal wear and no corrosion. Crankshaft bearings had minimal wear (so little that I wondered why we were replacing them) - they are cheap, and since we were in there... There was no evidence of any blow-by from the rings.
I would not open up a problem-free engine just on the basis of hours run. If I hadn't experienced the set screw issue, and my engine was performing as it did, with good compressions and oil analyses, I'd take it to TBO, or beyond.
Steve