I have access to a Rieger tracker pipe organ which has the drawknobs (left to right) on the left side of the manuals = pedal then great. On the right side of the manuals (again arranged left to right) = positiv then swell.
My HW organ has (left to right) on the left side of the manuals = pedal then swell. On the right side of the manuals (again arranged left to right) = great then positiv then solo.
I don't know if there's a correct way for it to be done. It just so happens that both instruments have the positiv on the right side of the manuals.
I prefer the great and choir/positiv to the right of the manuals and the pedal and swell to the left of the manuals because that's how the Casavant I did my degree on was arranged.