Being one of a kind

There's a commercial now (Fisher-Price) that contains a line promoting, "...being one of a kind..." I've used that phrase from time-to-time and heard it many times.

But I was thinking about it more carefully the other day and concluded that it doesn't mean what most people think it means:  It doesn't mean that you are unique.

According to Google, "kind" is defined as, "A group of people or things having similar characteristics".  So being "one of a kind" basically is like saying you are "one person in a bunch of similar people"...and what's unique about that?

So I was wondering: Did this phrase start as, "You are a kind of one?"