You only need one of the tags to get the bow. I played on a final stand only conquest large server and just ran around to each spawn point until I found it. I had to play each map a few times, especially giants of karelia. When I looked up tips on how to find them, a lot people used IR or night vision, MAV's/soflam, but I never found any of them using those. Having a flashlight on your primary or secondary is good for the darker maps like Hangar 21.
My gamer tag is: Red_Baron_1915