User blog comment:LunarWing/UPDATE is HERE/@comment-96.247.56.55-20140627153852

If it still was 2008/9 when the NX weapons were just reskins (G36e-    G36e valkire; Scar-l  - Trispear Scar-l, etc, etc.) it would make sence that if you buy a gun (ether perm or not) with gp or nx, selling it back was not an option. So in my opinion that they are not allowing people to sell back their NX weapon at the moment, is a good thing, that reflects how the game was before.

But now, I would not mind if they allowed you to sell back GP and NX weapons back, not just only NX weapons back, that would seem fair to me.