Locket necklace with photos Kennedy Martin Luther King

This is a really unusual necklace that features a photo of Martin Luther King Jr on one side and Robert Kennedy on the other side. It looks like it opens, but I tried to open it and I cannot get it open and don't want to force it. The chain is a gold tone, but I have no idea if it is real gold or not. It is 22 inches in length. The locket measures 1 1/4 inches in diameter. It is a nice little piece, and I cannot tell if this is something someone bought like this or something someone added these photos to. The photos are black and white, and if I had to guess, I'd date this to the late 1960s. The glass is curved. If you have questions, please ask. I'll be happy to answer any questions I can. Thanks for looking, and I appreciate all bids - the funds I raise on eBay go into my three daughters' college funds.