Here's all I could find:
http://en.m.wikipedia.org/wiki/Camp...(California)Or
http://books.google.com/books?id=OB...=0CDQQ6AEwBgDoesn't seem like anything of real significance in the scope of the Civil War. However, given the font and level of detail, I'd bet that's a modern (1950s or newer) medal. Given that the design was simply punched in, this was also probably an inexpensive medal; possibly a tourist item.
Creating dies was no easy process in the 1860s, and anyone who went through the trouble of creating a die would have also given the medal a reverse, or at least left it blank as opposed to being a mirror image of the obverse. Plus, nearly all coins used serif fonts in the 19th century, whereas this is a much more modern sans-serif font. Not 100% ruling out the possibility of this being from the 1870s-1930s, but the details just don't add up right for a 19th or early 20th century medal. I'd give 1950s-1990s as a liberal estimate, and 1970s-1990s as a conservative estimate.