Copyright laws are often misunderstood.

In reference to the year thing. The date published with the copyright is the original date of creation. If something says 2003-2005, then that means the original copy was created in 2003, and there have been significant changes to the item throughout the years, warranting new copyrights, but still protected by the original version of the item.

To fully understand copyright laws it requires some research of your country and state/province laws. Another easy way to ensure you have proof of date, print out the screenshot, source code, whatever, mail it to yourself, and keep it sealed. The mail will have a postmark of the date, proving the date of creation. Works well for written pieces and artwork as well.

Just my 2 cents. I know quite a good bit bout laws pertaining to copyright and fair use, etc, so if you have any questions let me know.