I've not done any proper testing, but I have a mix of these and the 12v ones in Plastic Fantastic and they look about the same speed at full throttle with the bot under no load sat in the cradle. Also it still drives straight, it doesn't pull to one side as it would if one motor was different. Therefore I think it is just a re-labeling exercise as said above. It would still be good to test with a meter to be sure