I need more Weapon Skins!

Like most Halo 4 players I have one gun with one camo color, an arctic skin BR but i was wondering how do I get more weapon skins and how many varieties are there? it would be a real dissapointment if all weapon skins were only unlocked through what store i decided to preorder from

From what I understand is that you can unlock more weapon skins but only through specializations. This Link goes over all the specializations and what they come with.

i just got my DMR skin yesterday through wetwork.

Once you hit specializations you get moar skins, i went the wetwork part and will unlock the Noble DMR soon.