Yeah, they're prehensile. Although I cannot imagine that they'd be used to grasp things. I imagine them as fairly sluggish and slow, and their form would make it hard to hold things, which is why I imagine that we don't really see them do that.
On another note, they really do have to fix how Lekkus look and function in the game. I equip a hat on Vette, they clip right through. I equip a mask, they disappear. There's not even an option not to show companion helmets, so... And how come there's not even an option on how to wrap them? I think a lot of people want Bib Fortuna's round-the-neck-over-the-shoulder Lekku.
Is there something horrible wrong with me, that when I read this thread the first thing that comes to mind is tentacle "intercourse"?
Welcome to the internet, where dignity goes to die.