Some of the AK gear got pushed to Pharos Sirius, including hoplite accessories. Whereas the Darklight Shield that was supposed to drop in Tonberry King has been moved to the last boss in AK.

I would say... do AK first to get your shield, it is very important. Then do Pharos Sirius (and Ifirit/Garuda) for your weapon.

I am not sure if you can get the same gear from both dungeons (or others) or just one, exclusive, dungeon drop. Time will tell.