I have flown the MIA-EZE-MIA LAN Argentina (4M) flight last December on the 767 in Y. I do not know if it is two or three class, but LAN's site implies that only the SCL-AKL and SCL-MAD flights are still three class. I assume that it's the new business class layout, but I don't know for sure. I don't remember seeing three classes when boarding, but I also wasn't paying a lot of attention at the time.