I followed the original construction, behind the partition wall behind the last row of seats, there isn’t any steelwork involved in the truss or integrity of the roof. In effect a network of steels for floors.
It could be done, but I doubt it will on cost > financial benefit grounds.
Rows could be added to the back of the NS, replacing the TV screen and offices. Without requiring alterations to the trusses.
The club show no interest in that though.