Until last year, Pauldrons were not considered a canon accessory for any Spec Ops troopers, but due to some digging and heavy lobbying on the part of our Fearless Leader, There are now 4 TXs that have Pauldron references, and to the LMO that's all that matters.
Blackhole/Shadow Stormtrooper: We can thank SW Galaxies TCG promo art for the black pauldrons on these guys. (Only black is acceptable)
Magmatrooper: The Gentle Giant Statue not only gave us the first item carrying the "Magmatrooper" name, but also gave us a nice black pauldron for it! (Only Black is acceptable)
Novatrooper: A commander version of this is shown in SWG with a gold pauldron, and is the only difference from the standard Novatrooper. (Only Gold is acceptable)
Novatrooper Elite: The only version of this that we have has a gold pauldron, so the gold pauldron is a requirement and not an accessory for this trooper. (Only Gold is acceptable)
Hope that clears things up. When the new CRLs are launched, this will be made clearer.
-iz