On the flipside, 52 has been mentioned in the LSH series previosuly. In #17, the Dominators discuss how their techno-organic payload has been delivered.
After that they state: "Existence is a loop. Time is a circle. And hate is eternal. Remember the fiffffdeetu." This actually debunks Geoff Johns' statement in a recent Newsarama interview that it's the first time "52" has ever been mentioned as a concept (not as a series) in the DC universe. Give or take the way Dominator's talk (with all that teeth!!) and the possibility of mis-pronouncing some words AND given that Mark Waid is one of the writers on 52 (the comic), then perhaps this is a clue as to what we'll see in DC's missing year?