Ok so ive been using the GEK-38 assault rifle and ive noticed in youtube vids of gameplay; that theirs is white and has a better iron sight then mine, and is also stronger then mine. soooooo yea help ?
The latest build has only been out for a couple of days. In almost every new update, they've changed the colours on some items. The video you watched was probably older than the latest patch for the game.
As for the damage, if you train Assault Rifle Operation to max, it unlocks Assault Rifle Proficiency, which gives a damage buff for the weapon. You can also equip damage modifiers which give a further damage increase. If a player did either or both, that will mean they deal more damage with the same weapon.