Not necessarily, the nut could be soft. In a corrosive environment, "string gunk" can build up in there. I've never had problems with my guitars, but as a repairman I saw a lot of things. Bone is very hard, but can have porous sections you have to watch out for. If a nut slot lands on a porous section it can bind and also wear the slot down over time.
Anyway, I would rather have the Schaller roller tune-o-matic with the fine tuner tailpiece. I think Ibanez blew it on that one. I love the guitar and would want one, but I just can't see cutting and locking a fixed bridge. They would have sold many more IMHO if they used the roller/fine tuner bridge. And with that, you can still have the lock nut if you want to!
I wouldn't mind getting a JS2000 and converting it to a lo-pro just for that color.