Ok, so since there are about 100 people a day on here asking how to get it, I will explain how. In no way, shape or form do I support glitching. But this really isn't a glitch, just an exploit to get the gun early.
And before I start, the golden ak is no different than the normal ak. It has the same stats, only difference is its is golden. And you cannot put attachements on it.
Step 1:
Go create a room. Restrict all weapons but the golden ak and ak74. Create the room, go into lobby.
Step 2:
Now, back out of the room and go straight to quick match.
Step 3:
Go to edit loadout for mercs. Switch your pistol. Then play a game or just back out. You'll have it till you switch your primary weapon.