Have you tested this in ygopro? We get the same information that all other ygopros get from the core. In general, if you didn’t shuffle your hand, then the order of cards in your hand didn’t change. That means, the one you revealed - you should remember and pick that one.
I will say that the cards that are revealed in your hand should have a eye icon or millennium eye icon. However, if all 3 heavenly prisons are revealed, then you have to remember the order.