It's option 1. I forgot about that strip when I assigned which character would cast which divination spell. I tried to give Durkon the lowest-level spell specifically because he said in #875 that he had no spells above 4th level except for Thor's Might and Planar Ally. So he couldn't have had True Seeing, and Locate Object is not a cleric spell.
In other words, I remembered the more plot-critical spell issue from three months ago rather than the throwaway line from a year ago.