The Awake! magazine said that the names of concentration camps such as Dachau were unknown before the end of World War 2. This is false.
Historian Laurence Rees states that they were very well known worldwide and quotes a number of sources to make the point. But he is not even trying to prove the point, he is merely stating the fact. Because outside of the 1995 Awake! the idea that names such as Dachau were "unknown" is itself pretty "unknown".
The extent to which the outside world knew about the Holocaust from 1942 onwards is a separate issue which does not relate to widespread knowledge about concentration camps. JWs were inmates of concentration camps from 1933 onwards and spoke about their experiences there, as did many others, as worldwide media reported.
JWs were not sent to extermination camps (unless they were also Jews) when the Holocaust began, so they could hardly report about it.
I suggest you read more about the subject to appreciate the distinction between concentration camps and extermination camps, and between JW experience in concentration camps and Jews during the Holocaust.