Copyright diffesr from country to country.
If its a company copright it can be up to 100 years from creation of item, if its private then it can last upto 100 years after the death of the copyright holder.
I have not read or wish to investigate the copyright issues of the data/application, but your best option would be to contact the copyright holder directly.
Even if they say the data is free, it is probable free for YOUR personal use, and you are not allowed to re-distribute, give it away, sell it within another application etc etc.
If you wish to do that then you would normal have to contact the copyright holder to get a license to allow you to use the data in that way.
If you wish to create an application that is using copyrighted/3rd party data, I would seriously suggest that you contact the copyright holder of the data; and explain what you attempting to do with the data; and see what they say. If you have to pay a license fee, this may in itself stop you in your tracks..
I am not trying to be negative; but I would not attempt such work if I did not have clarification in writing from the copyright holder that there would be no problem and I was safe from any legal issues down the line.
The fact the file you have does not have a copyright notice, could mean that the general copyright notice of the application takes precedence; which may now be more restrictive than before.