Forest boss Megson said last week that Weymouth were now favourites to win the tie in front of a full house at their own Wessex Stadium.
The bookmakers disagree though, making the Reds odds-on favourites for the live Sky clash.
Graham Sharpe of William Hill told the Evening Post last week: "Forest are 250-1 to win the cup and Weymouth are 7,500-1. We think those odds are realistic and that's why there is a difference in the prices for the match itself.
"We don't tend to take a lot of money on these sorts of matches because Weymouth are such a big unknown.
"If we take any money, I expect it will be on Forest. People will be convinced they will not slip up again."