Sup, this was a project between Me (Goohp) and Ville88 to add all the Bo2 Zombies skyboxes into Bo1 and its Modding scene.
 
The textures and all were extracted using Tom Crowleys Bo2 Ipak Extractor. With that I went in and grabbed each refrence to a skybox and fixed them all so that they were convertable and acceptable to the asset converter.
 
Ville88 did the converting part. Huge credits to him, I legit couldn't have done it without him. Bo1 is weird.  
(Credit from my part isn't nesscary, but It might be for Ville, so keep that in mind before adding these to your map.)
 
Keep also in mind that certain skyboxes are low quality because of how Treyarch would of used them. Ones like the Tranzit/Greenrun ones are pixelated and stuff because normally in game you wouldn't have seen them or seen them well, so there wouldn't really have been a purpose to make them High Quality. These original skyboxes were very low quality, so keep in mind how you'll use them.    
 
There will be progress on a Campaign and Multiplayer Skybox pack when given the time. So look out for those!
Anyways, goodluck and happy creating!
 
https://www.mediafire.com/file/j8x6ylwyox9oopd/BO1_-_%2528Bo2_Zombies_Skybox_Pack%2529.zip/file