Is this a vintage cameo?

I bought this necklace from the thrift store, I thought it was pretty. I haven't worn it since I bought it and I was about to re-donate it, but I flipped it around and it has something maybe a signature? on the back. I was wondering if it might be a real vintage cameo worth keeping, even if I don't wear it. Here are a couple pictures:

front - http://tinypic.com/view.php?pic=33e3rex&s=6
back - http://tinypic.com/view.php?pic=2n8oroi&s=6

Also, if this is something I'd have to have somebody check out to know for sure, where would I go for that? I have no idea about this stuff. Thanks!