Model Changing help.

Okay. So i tried to turn my M16A3 into a Ak103.. Regardless i renamed all the right files. When it comes to injecting them I put Ar into the file name, Then add the 3 files i renamed into the program It Always comes up as Not Found. Is that normal? Also when i click inject. It says something like these duplicated files were not found would you like to skip these files? And i click yes. Anyways i put it in the folder rename it delete the original, When i go into the game all my guns are missing. Can anyone tell me what i did wrong?

renameing the file wont change it u have to copy all thats in it with hex editor and paste into the thing u want to change