The seat backs on '11+ have the seatback release handle on the side / rear of the seatback that the '10 and earlier don't have.
So there'd be a hole in pass side rear seatback (rear panel) where you don't have that release handle.
'10 pass side had the release lever on back on the seat.
I've attached images of driver and passenger side seats that have the '11+ style seatback release.
While you could cut an opening for the side seatback release handles - you'd have a hole on the back of the passenger side one.