ah textures, textures should also be in the same VPK but they would either be under cstrike/models/textures <-- which I doubt
or something like cstrike/textures/weapon
either way they are VTFs, GCFScape has a built in search function (ctrl+f) and you could try searching for the texture by the weapon name. ex. searching “p228” would return the model, but also anything else that has “p228” in it, like textures (vtf’s + vtm’s) and physics for models and the like.
I also suggest you use the new wiki as much as possible, while the old wiki may have some miscalanious information the new one doesn’t the maurtus.tv one is partially outdated.
[editline]27th June 2013[/editline]
also: http://maurits.tv/data/garrysmod/wiki/wiki.garrysmod.com/index7b77.html <-- gives a bit more information on setTextureID in case you didn’t already look at it