kl644 is 747 with old WBC - on it a couple of weeks ago. Do not remember food as I was trying to catch some sleep but think only snack snack. Would suggest that if you can get the kl642 at 18:15 go for it. Entertainment is much better (although you will most likely be sleeping) , seat is in my opinion better, unless you can get row 77 and then still I feel that comfort is much better on 777 (I know not everybody agrees on this one). Enjoy the flight