[Marttt]

AFAIK the m_iAddonBits is just an attachment that doesn't represent a real entity, if you manipulate the values you can see that you can add at to your body some equipment that you don't have, like the gascan (from hardrain)

I think they added weapon skins to the game but wasn't implemented 100%

Maybe you will have to change some files through a vpk to achieve that.