Good point, all true. And also if the previous owner(s) wore rings there may be a bit more wear and tear on the steering wheel / gear knob, so not the best indication 4 u.
If you can, ask the seller if the 100k major service has been done (and have receipts). If I was buying a car with for example 70k on it, i'd probably be doing the 100k early as you cant really verify the km anyway (And like my mates r32 with 90,000 on it u might find a sticker saying next change due @ 200,000 under the cover.....)
If seller has no confirmation or receipts, maybe another negotiation point 4 u.