No, I mean a take-off: someone bought a bike and had the cassette swapped, so they would put that on your bike as "new," even if it had a handful of miles on it.
If you have a new chain, or just a few links taken off of a shortened chain, you can wrap them around those cogs and find out if they are genuinely worn. If they are, the chain won't want to engage the teeth, or the chain won't sit all the way down to the bottom of the teeth. If the links slide right on, the cogs are fine.
__________________
