My snakes are more comfortable with me than other people in the household but I don't think they RECOGNIZE me, exactly.
I am more comfortable holding them, so more secure in how I handle them.
I have handled them more and know their preferences.
I am generally warmer than most other people here, who run kind of cool.
I also think though that they're fully capable of recognizing that a given scent is associated with 'not a threat' and that applies to people and the way they smell, too. I handle them a lot more than anyone else and I'm pretty sure they're all capable of realizing that that smell means 'warm furniture' rather than 'potential predator'.
That's about as far as I think it goes, though.