I agree on this, I've opened 4 engines now... all of them well worn out. All still standard sized pistons... (doubt any have been opened before.)
But yes, there was pitting... and pretty much an every lifter, but the cams all looked ok, all with same sized lobes. So I guess pittings can't really hurt too much.
Oh, I asked the prof of the automotive department in my uni, he worked in germany for mercedes for 20 years... and he said, "Pitting is alright, it's a normal thing... stuff has to wear... don't worry too much about it, other parts will wear out before these..."

So now, in my fresh engine, it has the hollow TRW lifters...(same as the new Volvo lifters...) it was the only part I could get locally... and they were cheap too. I hardness tested one... (for fun... only 2$us a piece anyways) it got 30HRC... not bad for the price... I'll cut one up when I have time...
I haven't tested the worn parts yet, but I will do that too...