[jeruku]

Cross referencing any related achievement(s) might work. I'm under the impression world quests all have achievements, I could be wrong, but most I've done have some kind of achievement for "completing" all the variations or simply repeating them multiple times; the criteria can be things like times the quest was completed, what rewards you've received, which NPC you performed the quest with, and others. Thus checking for the presence of a completed criteria would indicate the world quest itself had been completed at least once.

Also not sure on this but I believe all world quest related achievements contain the title of the quest, in double quotes in their descriptions, which should mean it's possible to scan the description of achievements for the quest title.