If the flight is oversold, an operational upgrade may be possible based on your PM "SkyTeam Elite Plus" status, although I would think that KE elites would receive priority. Never hurts to ask anyway.
You just missed out on the SkyMiles upgrade award certs on KE fares. Upgrade award certificates for KE flights were discontinued beginning 07/01/02. I picked up 2 award certs before the deadline and am using one in September.