[Gasser Nate]

You can never be sure a speedo reading is accurate unless you have owned it from new.
Always go off the bike condition. My 2018 has 2200km on it but looks like it has spent its time sliding down rock faces because I ride tighter rocky nasty trails.
But it is mechanically perfect.
Try not to stress on what is regular use and look at the bikes components to judge value.
I have seen worthless bikes with low ks and mint bikes with 150,000ks.