So your saying you want the zombie hands on Model Pack 10 weapons? Sure it's possible! It fairly easy as well!
1. Go to here:
C:\Program Files (x86)\The Game Creators\FPS Creator\Files\gamecore\guns\Model Pack 10\UNARMED3
2. Copy the file called Hand_D.jpg
3. Go to here, and choose the gun you want to apply it too:
C:\Program Files (x86)\The Game Creators\FPS Creator\Files\gamecore\guns\Model Pack 10\
4. Open the gun you want zombified and paste the Hand_D.jpg into that folder. PLEASE BACKUP THE ORIGINAL FILE JUST INCASE YOU WANT TO GO BACK!
5. Now i would run the FPSCreatorCleaner just in case. I don't know if it matters or not, but i would run it.
Hope this helps!