In the photo of the new MC toys the guns he is holding have the same color on the trim as his armor. It could mean that you can customize the color on your guns.
http://www.halodestiny.net/news-1783-les-figurines-du-major-et-de-sa-cryotube-en-images.html#skip
I hope we don’t get to customize our guns. It’s just exaggerating in my opinion. We don’t need that much customization.
God I hope not.