Copyright notices are really just a signal for the users, and to say "don't steal our stuff" in somewhat of a non-forceful way. People can generate the year automatically, but sometimes they just forget to include it.
Is it a big deal to have an older date? Probably not. Google has a number of other ways they could check a page's freshness aside from a completely arbitrary copyright date.
An interesting note about copyright, you don't really have to display a copyright notice in the first place. As soon as you create something, it's already considered "copyrighted."