No, even the series2 were stock parallel loops.
I've always read that on the dual/triple you shouldn't run the bold and diode settings with EL34 tubes, but on the series2 single they have the EL34 option and all you can run is bold/diode settings, obviously because that is all you have on the single.
My power tube preference is 6L6 anyways, so for me it doesn't matter, but I have never understood why on the dual/triple you shouldn't, and on the single it's a given that you do. (?)
With any 6L6 in a rectifier I try to use green or blue color codes. Makes a slight difference over the usual reds and yellows that are stock.