I agree with you. But how do you find out who owned it? Did people actually own apartments back in the early 80s?
Well, yes. It wasn't public housing, owned by the government. Somebody in the private sector owned it. Whether it was an individual flat that was owned, or the entire building that was owned, somebody owned it.
NYC apartments are peculiar. Getting into a rent controlled building is a coup, because it's very expensive to rent there, even in a poor economy such as the early eighties. If it was not rent controlled, and was such a deal that he could almost immediately sublet, legally, somebody did him a favor, and that somebody likely knew he was coming.
So, you might take some of the mystery away, from at least one benefactor.