To the player, it doesn't make any difference if cards have been preselected as replacement for discards or if they are newly selected when you push the Draw key. You don't have access to the information until after the hand is over in either case.

It is of casual interest only if you play the "what might have been" game and want to see if your play resulted in a poorer outcome than some other play might have. You can't change your play based on how lady-luck treated you on the last hand. She will do as she wishes next time, bound only by the long-term laws of probability. If you are a regular player, it's best to learn the strategy that will give you the best return on your play and don't deviate from it based on hunches or past play.

Remember, the long term is a really long time for most players. You will have to play hundreds of hours to start approximating the theoretical return for the game you play. If you plan to play only a few minutes, play your hunches, as it won't make much difference over that short a time span.