It was definitely still part of Facebook when it started rolling out beyond colleges to high school students around 2005/2006. I remember people spending way too much time rating randos in study halls back then.
But I have a feeling you are confusing things and timelines. Perhaps you are remembering the actual hot or not site that did just what you remember while thinking of the facemash or whatever that Zuckerberg made prior to FB that we probably all learned about when we watched The Social Network.