Yes NOS = new old stock.
The KS mags seem decent they are south Korean made but work well.
Used to be cheap but KS never stocks them anymore. And they were the sole contractor importer of them.
Unfortunately like all surplus it's no longer is surplus so all the 3 and 5 dollar mags are gone and all the 20 and 60 guns are gone.
New gun owners missed all the above its now surplus is collectable and collectable starts out at 1200 and up entry level.
GG mags, the midway m1 carbines, and those dumpster barrel nagant rifles, just to name a few.
Anywho
I too prefer the blued GG mags over the parked ones. They seem to fit my mag well better be it the KS or GI mags.
Ironically i only have one OEM GG mag that has the cobrey logo on it, it was purchased off of fleabay back when you could still sell that stuff there.