The way they do it is have a small "business class" on the upper deck of their 747-100, with probably 12-15 seats. On the main deck of the 747, it's all economy seating for about 560 people. The numbers of galley and lavatories are kept to a minumum. Yes, you can pack that many people in there.
In the US, Tower Air does the same thing on their aging 747-100s.