Maybe ask @Xerp and he might be able to make a custom nade skin for you? idk EDIT: Oh wait, he is banned
If this is no memes, yes you can skin every pixel you see on your screen. The texture for frags are in /weapons/ called v_eq_fraggrenade_xxx and also have w_ models with same name. If you have CSS, they are in your CSS folder, but you can just put a file in your /addons folder to overwrite them.