It’s funny that this all turned into a conversation about the corp, when the original question was a specific nuance of Apocalypse / Hunter Seeker, now that Assimilator exists to flip those cards back face up. The person (over on FB) was asking if the runner had to divulge which facedown card was a particular card (like Magnum opus) that had been turned facedown. I say they don’t have to divulge, as long as they didn’t obscure which card was which by moving them around.
But the Corp game has not, traditionally, involved caring about the position of cards in the runner rig, so this is a new memory space to pay attention to.
Thanks for the great discussion, everyone!