[Jaypack44]

I'll tell you how: download the sfs extractor tool from here, and etract all of the sfs files to a folder of your choosing. then, go into the extracted files, and open the following folders: paintschemes/decals/and then there are all of the files for all of the game markings. if you already know how to make a mod and put it into the MODS folder, then you're good to go. if not, let me know and I'll explain it for you.
HTH!