There could be something in this. My chocolate foot is my left and I drive a manual shift too. And btw the pedals are not reversed when the "handedness" of the drive is changed. Those of us who sit in the right hand side of the car to drive still push the clutch in with our left foot!
I always thought my left foot was chocolate because I am short (and lazy) and when I pull up at the lights (on the left side of the road) I unclip and roll up to the kerb and plonk my left foot on it so I don't have to get off the seat.
Or - that I am quite right foot dominant and so I like to get a good push off with my right foot on the pedal?
Maybe all of the above?