Yeah! Stealth means nothing when your ranged attack maxes out at 4"
Have you seen my shocktroopers/demo corp? I specifically split up the fancy shoulder pieces across the five guys as a way to tell them apart when tracking damage. So I've got:
1. Regular Shoulder Pads
2. Shoulder with the + sign
3. Shoulder with the individual star
4. Spiked Shoulder
5. Khadoran Anvil on the other shoulder from the others
Then, I can draw little symbols representing the shoulder pads next to the damage boxes for easy reference.
Moral of the story: claim you did it on purpose, like me. As for decals, I'm guessing you mean the rank symbols from the forces of Khador book? Pretty sure no decals exist, but it should be good freehanding practice since they're all relatively simple and build off the previous rank.