Question about BO 3 and 4 zombie models.

[JohnSmirnov]

Hello! I am not sure if many people noticed it, but it appears that zombies on all maps in both games have various model details (such as heads, gear etc) missing or simply not spawning in PC versions of the games, just like shirtless zombie German from BO2 Origins map. If not a problem, can anyone who worked or checked on various zombie models and details tell me if they are in the files and can be used for modding, like for custom maps? Examples: mustached SOE zombie male and female zombie heads besides lady with a bowl haircut, ZNS hats worn by zombies on that map, various head models of zombies from ZC maps, various head gear and head models of Gorod Krovi zombies, and various head models and head gear of zombies from Classified, BOD, IX, VOD and DON? (Also heard that Nightmares and DOA2 in BO3 are missing some head models too, but not sure about that)

I of course can try to check it myself, but what programs do I need to use to view them and where various zombie models and their details are located in the files? Sorry if the questions sound stupid, I am just a newbie with extracting and viewing models.