You'd better call Korean air to find out. Actually what happens is if you say your reservation number (6-digit-alphabet and number thing) then they will answer what the machine says about, "AVOD or not". So I'm not sure how nonrev thing will be. And the seat arrangement is different, old ones are 2-5-2 and new cabin has 3-3-3. I think new 777s are going to DFW
randomly, not regularly. Not that much helpful to you, sorry.