I don't know if it's just me or if other people out there are having this same problem, but I'm having a hard time understanding the unlock system in Gears 3, It seems very confusing.. For example; Say I'm checking out the Stats and Awards section and I want to look at my weapon skin unlocks, I tab over to the "Challenges" area and click on the "Weapon Skins" sub-menu. From there it shows you a list of all the possible weapon skins you can unlock, but it doesn't do a very good job of displaying exactly how to unlock the skins.. Don't get me wrong, some of them are made very clear by telling you that you just have to reach a certain level or obtain a certain achievement and those ones I understand, but some of them are not as clear. For example; to unlock the "Gold Gnasher" skin all it says is "Old Guard" with a 0/1 next to it. Nowhere does it tell you what "Old Guard" is or how to get it.. This is just one example, I've come across many unlocks that I couldn't actually figure out how to unlock because it was not made clear. Is it just me or is there some menu that I am missing that helps explain this stuff better? Thanks GB community for the help!!!

All of those are Medals or Achievements you have to complete.
 
It is very unorganized and I suggest looking up some kind of list online if you want to know how to get specific unlocks.