english is correct, the red dot is supposedly used to orient the shaft where the spine of the wood is in the ideal position where it doesn't bend side to side as much. the black dot is also supposed to be used similarly, dot up for both. the only difference between the red dot and black dot is that the black dot is flat laminated. i've tested these shafts and i couldn't really tell any difference with the dot in different positions. snooker players though always hold their shafts in the same orientation, so maybe there is something to it.
the no dot shaft has a different ferrule design, it's basically a classic straight through tenon design. i believe the material may be different as well, the ones i saw were more ivory colored, whereas the red/black dots used a whiter material. the tenon design, along with the possibly heavier/harder ferrule material, would increase deflection some. the red and black dots have a hollow space up front under the ferrule. the ferrule is capped and if you could see the tenon underneath, it looks like a sharpened pencil. that removes some weight and also is claimed to allow the ferrule to bend around the tenon to reduce deflection.