Considering that most people can't identify most Middle East locations that frequently headline news stories on a map, it is safe to say that their locations are not commonly known by many Americans. It is possible, however, that people in other parts of the world are better educated in geography and can quite easily identify the locations on a map.
To say commonly known may be a bid misleading. I know I don't know them and I think the average American does not know them. However if you ask about people in higher up positions in the government and military there is a good chance they may know them. So no it is not that common.
Outside of Syria, few people know what is going on with the current conflict. The locations of towns and suburbs are rarely known. One is a suburb of Damascus and another is near Aleppo. The conditions of these towns are unknown as fighting continues in the Syrian capital. Many outsiders only know of Damascus and Aleppo in terms of the Syrian conflict.
While we might know the locations of Al-Zahra and Al-Nobbol every so often, they tend to move around. The United States can't keep constant track of these individuals, despite the country's best efforts. Then again, tracking two individuals that are trying to stay hidden often proves difficult for most pursuers.
The locations of Al Nobbol and Al Zahra are not considered commonly known, at least not at a global level. They are still considered under the radar and they do not pop their heads up very much. Because of this they don't hit the media and are not easy to find.