Is there a copyright sign somewhere? If so, and even if there is none, you can assume they are not free to use in OSM. When in doubt (and you are and I certainly am) always contact the copyright holder and ask them a written statement that you can use the maps in OSM. Otherwise: don’t use these maps as a reference for OSM!
In short: the fact that you may use the maps for free does not mean that you may copy them. Copying maps is almost always NOT allowed.