steam key from old humble bundle games ?

I think he means from the ones that were when the OAuth method was used, and i think that you dont get steam keys from those games, they still are redeemed by clicking the button.

I recently won an old HB gift, and it was directly redeemed to my steam account, no key was shown ... so it's better to use HB gift function.
afaik HB mentioned that they'll warn users when they completely remove OAuth from old games.