http://www.seatguru.com/airlines/Cat..._747-400_A.php
Both of my flights will be on 744 aircraft, not 74J, so yes, it appears there is a lav on the 30 ABC side but not the HJK side. That row 30 HJK looks pretty appealing, especially if I wouldn't have to worry about people crowding my legs in the loo queue. I wouldn't care so much in 44A/K, but 44C/H look to be in the middle of the lobby.