I honestly don't know.
Newlie does not lick much as general rule, and when he does, it feels like it is for different reasons. For example, he will lick my hands if I have been eating something salty. And, although he has gotten better over the years, he still doesn't care for anything with a nozzle being near his ears and will lick at my hands and the bottle to try to keep it away. Then, there have been several periods of time when I was laying in bed, that he would start at my hands and lick thoroughly most of the way up my arms. I would eventually have to stop him because his tongue would start to feel like sandpaper. It sort of felt like grooming behavior, but the only times this happened was after a death, first my mother, then my husband.