Yeah both 2wd and 4wd use 12mm Hexes, but the axles on the 4wd car are the uprated ones designed so you can use Asscoiated wheels on them
Don't ask me why they did this but anyways this means that the 2wd wheels are not a direct fit onto the 4wd. Kyosho can be used on both but you will have to enlarge the holes to go on the 4wd, but it is the only way if you want dished wheels on both 2wd and 4wd cars with the right offset.