Really depends. You can just about avoid having any chance of finding them if you don’t do a few things with a fair amount of frequency.
1. Do you pursue tavern rumors of unique items that you hear when buying a round for the bar (not for your company)
2. Do you visit armories frequently? The chances that this will work are greater when you have good standing with the house that owns the armory, and after escorting a caravan to a stronghold with an armory.
I’ve seen them much less frequently in the hands of bandit leaders and orc warriors. Of the above two strategies, I’ve found the second most useful for actually finding unique items.
