The 3 pics you showed, the first two are the pre-pro2 suit, the most commonly known pre-pro suit, the 3rd pic is of the pre-pro1 suit also known as the eyes suit. I am one of the only known people to have a completed Pre-pro suit, (pre-pro2). As far as anyone in the 501st is concerned any of the known pre-pro suits would be considered cannon.
Just FYI there is a pre-pro3 suit also. Very few pics of that suit exist there are a few in the original Chronicles book.