f-ck I forgot
welp, files I had are no longer there
alas it seems someone ported this model to L4D as well https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=2924601423
high chance it's the exact same model as the og mod, not this resize

gonna update the desc a bit...

Bruh why not that workshop model banned or hidden.....

You don't have to answer my question below. I checked the model in blender that your edited model with low textures, that from Left 4 Dead - there are no facial bones for posing. Maybe the original model made by Ayabe Misotsuki has them, but in the ports they are not there for some reason.
(P.S. I don't think I can make facial bones for this model. Even though I know how and there are guides, but it's too painful. Even just selecting the lower part of the jaw to make the "Jaw Down" bone would take some difficulty that I don't want to deal with).

Do you know if the facial bones(Face Posing) were on the original model?
(P.S.:In your condensed version they are missing).

I do not
maybe the original mod had, but as it stands all you can do is use some unpacker to pull out the files as they are here. I will get to posting the OG eventually as I do have the files around still if you care for the textures

Do you have a link to the model? (like on 3d models website)