Google says it is[0]. It might be true because when you get street address from Google, you are also getting the mark on the map for the location. Whether it's true legally or not, it's better to stay away from their data. That is, if you use Google maps, you agree their terms and thus you are not allowed to copy the data.
And btw, I have seen (possibly deliberate) mistakes in street address markers in Bing maps (which is the recommended map[1] to follow for Open street map editors). So don't think that they won't find you if you copy their data).
[0] https://developers.google.com/maps/terms#6-googles-proprieta... (The definition of Content is explained in the following section, which says "... and places data (including business listings). ")