I think it might be random. Card 81, which I think is the one you refer to, either brings in cards from the deck (which will be random), or from the discard pile, but the card does not say how they are selected. The only other card I have to go on is 87, which allows a random player to receive a random object from the discards.
Thanks! I did see card 87, and that was the only help I found to come up with a guide. So I would play it with the random option. Thematically, you already searched the wreckage, however. So you know what was there, and presumably where it was on the island. I could see an argument to support either way. I think I like the random option.