Supposedly, at check-in the OP will be able to choose a seat in Rows 1 or 2 if still available then. Also, there has been one report of an FTer that paid a D fare was contacted by United they moved the seat to one in the former First Class area. That must have meant that there were no GS and that that FTer was chosen due to the higher fare paid (meaning that would not happen to P or Z fares or upgrades)