In 
CompoPack-KingGen/CPVANILLAKINGGEN13PREFABLIST.txt at main · stallionsden/CompoPack-KingGen (github.com) I see these duplicated POI lines (line number : prefab name):
72:blueberryfield_sm
			130:cornfield_lg
			131:cornfield_med
			132:cornfield_sm
			369

otatofield_sm
			538:water_tower_01
			539:water_tower_02
			540:water_tower_03
			630:blueberryfield_sm
			631:cornfield_lg
			632:cornfield_med
			633:cornfield_sm
			634

otatofield_sm
			635:water_tower_01
			636:water_tower_02
			637:water_tower_03
Edit: but darkness falls already includes most of compo pack's POIs (and edited versions of them, for balance reasons). Anyways, I was not looking to combine compo pack with darkness falls -- I was just using the compo pack poi list because it was the only example of a poi list that I had found.
Anyways... now I understand that the "Generate custom POIs list" feature will build the thing for me. So that's good. (And I checked the poislist.txt generated by kinggen -- it doesn't have any duplicated pois.)
On the other hand, it seems to contain 844 pois, and the prefabs directory has 893 pois. Kinggen has tossed all the POIs whose names begin with two 'A' letters. Like AAA_quonset_01 ... or maybe those are not really POIs? It's odd...