My guess is this is just a vinyl sticker.
If so, I'm not sure how well they will adhere to the leather.
I can just see it now. A little edge peels up, your wife/gf/some chick is sitting in the seat. Her hair catches the peeled up edge, she gets out of the car and has a mustang decal tangled/stuck in her hair. You don't want to be dealing with a woman with a vinyl decal tangled in her hair.