Not technically because your link says "...that you know to have been obtained through theft or extortion".

But the records could have been taken from the trash. If nobody reported stolen records then they can't be considered stolen.

The examples under 1.3 [1] indicate that the standard isn't 'actual knowledge', but also include situations where the recipient 'should have known' that the property was stolen.

1: https://www.shouselaw.com/ca/defense/penal-code/496/#1.3

The old records may have belonged to the car thief. Given their low value, it's unlikely to be loot.

What if you found a jar of peanut butter in the car? Would you try to find out if it was stolen and hunt down the rightful owner?

Yeah, I was actually confused when I read that in the article...