A quick test shows it's legit. This is a modded bati2.ytd (I used bati_sign_4, and spawned it in singleplayer).
"The way I edit them is to extract the .ytd file from the game by using OpenIV. Then using Texture Toolkit to extract the .dds files from the .ytd file. Then use a converter to make those .dds into .png files and edit them in photoshop. After that, it's basically doing the steps in reverse to import them back
" - DrZepto on GTA5-mods.com
Again, don't use mods online unless you want a ban.