If you know what NPC has the conversation in question, it might be easiest to find the npc in the creature palette for the module, and then see what conversation it's running.
If you don't know that, it is possible to mass search scripts and convo, just using the standard ctrl-f text search. It has an option to search all files in the module. Unfortunately, it doesn't seem to search conversations for script names in the various slots, so that should find you the script that fires, but might not help on the convo.