I need info about the rarest item in the game, the lucky rabbit's foot

I've heard many different stories about the lucky rabbit's foot item in the nuka world DLC, but even though I farm raiders for xp and legendaries for hours sometimes, i've never seen one, and whenever I check the internet people split into two groups. Those who found it in vanilla Fallout 4 And those who deny it, and say it's a mod.

I'm doing a true 100% run, and I need this on top of my pile of unique stuff. So, does it really exist, or no?