74Fs don't carry freight on the Upperdeck, they have normal pax seats and rest areas (numbers dependent on series of 747 and fit out of airline). The are the upperdeck area uses of the maindeck accounts for the difference in height between Q6 and Q7 pallets.
Never seen a pallet with seats on, don't know why you would want to have one to be honest, plus I'm sure there would be all manner of safety implications, emergency exits etc