I have my father in laws firearms at my house while we sort out his health issues. This is the 5 shot .22 Derringer. I have absolutely no idea how to open the firearm I suspect it is unloaded, but want to make sure before I put it away. The trigger ring(?) is forward, like it's cocked. Any idea how much these are worth? I would call it fair condition, but there's no specific damage on it. IRC, last time we talked about it, he has fired it.