B747 Seat 61K

Just came back from Miami and we had the seats 61 H/K on both legs. Going out on Mustang Sally there was no actual window. Coming back on Tubular Belle there was a window.Does anyone know which of the other 747s are of the same type as Mustang Sally or is this a one of?
These are part of the seat pairs at the back of the aircraft which are great seats if you have a window..

Strange seeing as they are the same config ,I guess there must have been some tweaking in the layout dept between lady p and mustang sally