True, actually, I did not think of that. Under US law, however (as an example), there are no 'moral rights' like under EU law. Hence, you can just let him publish it without your credentials there if you are an American (textures have to be detailed though, unless they are completely your own works).
As for the 'date etc'... I don't think there is any metadata stored in the map files. Such metadata from the Operating System (Linux, Windows, etc) is not transported over the internet as far as I know, so it wouldn't mean you are the author.
Or you can always not use a license at all, which means it will be non-free (as in freedom). Though it won't be accepted in RE in that case, or any open source project.
You just wasted 3 seconds of your life reading this.