Korean Air operates three types of 777s, so you might be viewing the incorrect one on SeatGuru. To confirm which 777 model you have, try accessing the seat map on the Korean Air app/website, even if you don't intend to change your seat.

If the layout is 2-2-2, you're likely in Prestige Suites, which is not new but has a better configuration than the older Sleeper seats. AFAIK, newer Prestige cabin types are generally found on their A321neos, A350s, and 787s.