Can you reinstall the dashboard?

I need to get an original .icns file back and I don't know how to reinstall or get it back.

So I was a n00b and was trying to change an icon without seeing how to do it first. So I replaced the default dashboard.icns file with another one that i renamed that and now I can change the icon but it won't update in the dock. I was wondering if there was a way I could like reinstall the dashboard or what I should do because all my icons are changeable in the dock EXCEPT my dashboard one that I messed with and now I'm pissed.....ANY SUGGESTIONS?!?!? THANKS

Thanks

 

not to sound like a complete n00b but how would I go about doing that? would you know the steps?