While trouble shooting hum in one channel of my first build, I was tracing the signal path carefully and have come to the conclusion that one of the following must be true:

1) the potentiometer takes the input from the front row and sends it out the back and vice versa

or

2) the board is mislabelled

See included the image tracing the signal paths from each input all the way to their end points that connect to the output transformers. My actual board matches the diagram.

I looked at the input tube diagram and it shows pin 2 controlling 1 and pin 7 controlling 6 so I don't think the channels get swapped there. Do the signals swap in the pot? Something else I am missing?

With my layout it was better to switch the blue transformer outputs rather than the inputs. So I changed the inputs back to the original board layout and reversed the blue output transformer leads. This put my left channel output tube on the left and my right channel output tube on the right when the amp was right side up.