Yes, it does.
Just like dark skinned elves suddenly appearing, they were always there just not ingame.
And since in places like Hearthstone, there is depictions of Worgen characters with tails, so there is already precedent for this to be the case.
There is no lore that dictates Worgen, a race of bi-pedal wolf people, can not have tails, so no lore changes if they get that option.