I can confirm that Hicks is correct with regard to the OWLF Recordings being common on the Derailed Map. However, I read earlier in this thread or somewhere else--I'm not sure--that one must have a perfect match to keep the recording. I thought so, too, as I had found one on the Derailed Map in the big warehouse with the chemical bombs, but I found later that I had never lost it: I still kept it.