I don't know where this claim has come from about it being only the second GF to sell out (if it does)? My memory might be incorrect, but I'm sure the Bulls were half of three successive sell-outs in the mid-Noughties; vs Wigan in 03, vs Leeds in 04, and vs Leeds in 05.
Although, that was with the smaller capacity of 65,000, so unless they mean it's only the second sell-out since the capacity was increased