Do you mean you can't see the skin when you see the gun skin when you have the in your hands? or when someone else has it or it's on the ground?
If the skin doesn't have w_ v_ p_ versions of the skins then you won't see it right.
@gangta, wtf is that. He posted in the CZ forum about gun skins. Not CS:S about some glock crap.
You don't place it in a map.
Open "C:/Program Files/Steam/steamapps/YOURSTEAMACCOUNT/condition-zero/czero/models"
If you do not have a models folder, make it. Once you made the folder grab the skins from the file you downloaded to the models folder. Then open CZ and play. Make sure you do not have CZ open when you install them, if you do close CZ and then open it again.