Ah... I think I may have it... I updated the core info files and now I can see the Beetle named cores.
*edit* Yeah, apparently, even though I updated the cores, it was updating the old mednafen named core... after updating the info files, it now has the new ones... If I load the Beetle core I can see the info for the core normally.
*edit* ...and, apparently, the BIOS I used to use for mednafen is no longer the same as the one for Beetle. Walk away from this stuff for a few months and nothing works when you get back.