They both point to the same romset to save space (as well as the same image & video folders), and I'm planning on seeing which games require some kind of prepping to use in FB Neo so that I can point the Final Burn Neo Platform entries to those specific files.
I should mention that I have 2 Platforms for arcade games in LaunchBox - the default Arcade Platform uses standalone MAME as default, and a Platform that I named, 'Arcade - Final Burn Neo' which uses RetroArch's FB Neo core as the default. I only update every now again, so I'm not planning on staying on top of the MAME romset. But when it comes to the FB Neo core in RetroArch, I'm not sure when I should stop upgrading the FB Neo core so that I don't overshoot the MAME romset version that I'm using (currently MAME. you match the version of MAME with the romset version that you're using), so I only upgrade MAME when I upgrade my romset (I'm using standalone MAME by default with the MAME RA core just as an option in LaunchBox). I understand how MAME romsets & the romset/MAME versions work (I.E.