Can I get the really exclusive weapon skins on Gears 3?

I’m referring to the weapon skins that were used for a few weeks only, for example like the crimson and white gnasher called Tyranny, or the Judge, The Jury, and the Baird. Great, amazing weapon skins that are no longer available. Why is it not possible to mod those in?

I think its because those are limited weapon skins. I saw them on YouTube and wanted them but found out it was only for the first 2-3 weeks before GOWJ came out.