Where would that "allegation" have come from then? The ticket website and official site both say sold out, surely if they had more to sell they'd say so?
Think you need to read the FL rules again, it is at least (but not necessarily more than) 2000 assuming your ground capacity is above 20K. The 10% only comes into play, for example like at Withdean, when the ground capacity means that 2000 would be more than 10%.
Withdean = 8000 capacity...
The rule is:
Each Club must make provision for at least 2,000 visiting supporters at every home match or such number as represents 10% of the Club's certified capacity, if less than 2,000
Apparently not, Forest have been using the other half of the stand behind the goal for home fans this season, as they were expecting to be promoted and Billy Davies had spent so much on such an impressive squad of players.