Get an expert salvage kit (or a superior or perfect salvage kit), and salvage off either the Superior Rune of Marksmanship, or the Herald's Insignia. These can then be applied onto your armor, provided you profession can use them. What you have at the moment is monster armor, which cannot be worn by you.
Yea I don't think any of your armor pieces are worth much. I could be wrong though. If the sell value of the superior marksmanship rune is less then 100g, merch it. Unfortunately when you get a gold armor, they are usually worthless, except for a superior vigor rune. Blue armors are better and yield more money ;-)
Expert salvage the Marksmanship rune- it's worth more than the 140g the armor piece is valued at! (plus, you may get lucky and retain the armor piece to sell seperately)