User blog comment:Martialmaniac/Uvo's Nen abilities/@comment-26871105-20161106034907/@comment-5780397-20161106104030

My points are simpler: the Nen template is for Hatsu abilities; if a technique does not use Hatsu, it should not be mentioned in the template, but if it does, even if it is unnamed, it counts as a Nen ability, so it should be there. Ko uses Hatsu, but of course we consider it a Hatsu ability only when the character regards it as such.

Uvo's durability was stated to be due to his aura and mental strength. He was impenetrable to cutting and slashing from the moment he woke up, because that's when he started using his aura. Of course, he is more durable than a normal human being even normally, but keep in mind that Kurapika did not want to kill him, he was attempting to get information. Nothing we have seen of Uvo allows us to assume his body is more durable than average if he does not use aura.