Not necessarily. To take The Predator as an example, I have a cousin who's older than I am who'd never heard it before. My cousin, brother and I were together, and I was talking to my brother about a song on it and I included my cousin in the conversation since my brother wasn't born yet when The Predator dropped and thus wouldn't be familiar with the song, but he didn't know what I was talking about either. I was in high school when it dropped and he was in his early twenties at the time, so seeing how I clearly remember it I was baffled as to how he could have gone without ever hearing it when we're both on the West Coast, but somehow he had.
There have been other occasions where I've just assumed there's a shared understanding when I'm talking to people in my age group or above and was wrong. When talking to people younger than me, I assume they largely wouldn't be familiar with the music I grew up with (which is usually the case) unless they've demonstrated an interest in the history of the genre (I've conversed with younger people who are familiar with and enjoy what is "older" music to them), but people in my age bracket lived through the same period of time, so if they listen to hip-hop in the first place, one would think there'd be certain things they would have heard at some point, but this isn't always the case. For instance, one woman I talked to who was a couple of years older than me knew who Heavy D was, but somehow didn't know who Big Daddy Kane was. So sometimes I have no idea what people pay attention to.
