Pretty straightforward. Anything that drops from a Legendary could have CP in its resale value.
Either replace the ISO payout with some CP, or let the player choose, or give both. 1000-2000 ISO is kind of a pittance for a fairly rare cover anyway, especially if you’re in a position where you COULD slot a 5-star.
Off the top of my head, I’d say like 2 CP for a 4-star cover and 5 CP for a 5-star?