Thanks. I think SFO-ICN also operates with the 3-class 777, but sold as 2-class. Did you try to book C in the front section (F seats), either in advance or at the airport?

A few airlines currently (or used to) operate similar services (selling 2 classes on 3-class aircraft), including SQ (on some A-310 routes), Asiana, AA, TG, etc.