there wouldn't be any need to pull down the motor,
the scrutineers could always pull the spark plug out and check the length of the stroke with a long piece of plastic rod.
this would show up as being longer in the big bore/strokes, than in the standard motors.
Stroke yes, but would be hard to check a bore size i would think. ALSO based on my limited knowledge of the Anima (an most motors for that matter...) i would be guessing the stroke would be done to take the 150 out to a 190, however i would guess to get it bigger again we would be talking boaring the case (+ barrell) and using a bigger piston, in which case the stroke would not vary? Could be wrong though...