This works only in Arma 2 but you can get it in Operation Arrowhead if you have combined operations
Open Mission Editor (in Main Menu, Singleplayer > Editor)
Open any map you want
Then once its loaded place a infantry unit in any location you want and then double left click on the infantry unit until it opens the "Edit Unit" menu
Then put this in the initialization
"removeAllWeapons this; this addMagazine "30Rnd_762x39_AK47"; this addWeapon "AKS_GOLD;"
(You can multiply the "this addMagazine "30Rnd_762x39_AK47";" if you want more ammo capacity)
Then click on OK
Now press preview and you should get the Gold AK!

Be sure to leave a award!