Odd that GM made so many production changes like that? I have a 2011 LS and it has the the rear cup holders, and it does have a head rest(or little non retractable bump) on the center seat Go figure! Maybe someone on the assembly line was still a little hung over and picked various seat backs when installing or maybe they ran out and said hey lets try these Eco seats! Didn't really matter to them, they fit! Who would notice or say anything about a headrest. LOL