Rabbits are real. Rabbits have feet. You meant to ask whether they're legit lucky. Any mocking this thread can supply is deserved.
So are they lucky? They can be.
Luck is more complicated than people seem to believe.https://www.youtube.com/watch?v=O4mN33w5Ftw>tl;dr
You have to get out and around and be open to fortunate shufflings of the cards. The world doesn't like you enough to kick in your door and gag you with a solid gold dick.
So if you believe in your lucky rabbit's foot, you'll have confidence, which is functionally luck as long as you're not a Darwin Award nominee.
Now the other side of it. After much observation I'm convinced that objects can actually exert influences. Things can be lucky or unlucky. How they acquire these conditions is not well understood, but since we've already established that it doesn't really matter, there's not much cause for concern anyway. But it certainly wouldn't hurt if the foot was the left hind one of a hare's that was shot on the night of a new moon by a cross-eyed man.
Think something might be lucky? Carry it around and see. If, instead, you're angling for a cheap and easy shortcut to better breaks in life? Stop wanting that.