Weapon cubemaps?

Hello, I wanted to know how to find all the cubemaps from gmod, to apply them on the weapon(vtf + vmt) just as valve did, also I’d like to know if the specific “cubemapgold001” exists in gmod, if not how do I export it, and put it on my gun, just as I said, valve did, an example from their vmt would be:

// Begin GOLD look

	"$envmap" "cubemaps/cubemap_gold001"	
	"$envmaptint" "[2.5 2.5 1.15]"
// End GOLD look

Custom cubemaps are saved as normal textures, and can be found in the VPKs for GMod and the Source Engine. Default cubemap layer just uses env_cubemap