[Mondial]

I believe that the power transformer does in fact have an interwinding shield. Tim mentioned a green/yellow wire with no seeming connection to the other leads which he connected to chassis ground. 

I would remove the line caps as they really don't serve much purpose in this case as an RF bypass for interference suppression. As to MOV protection, A tube amp is pretty much immune to line spikes considering tubes are very rugged and can sustain peak voltages of thousands of volts without any damage.