If you need two similar google maps, and you don't want to create all labels again, you can copy a map from "My maps" doing as following:
- go to the map you want to copy, and copy the URL you get click "Link"
- paste somewhere else that URL and add "&output=kml" at the end
- now copy the whole new URL
- go in "My maps" and click "Create new map"
- then another link saying "Import" will appear: click on it
- paste the URL in the string filed and click on "Upload from URL"
- now you have your copied map!
