Right, in 1997 they switched from lard to partially hydrogenated vegetable oil, aka vegetable shortening. They used hydrogenated oil because it has roughly the same consistency as lard. That’s because hydrogenated oil is saturated making it solid or semi-solid at room temperature. If the current OREO ingredient list doesn’t show hydrogenated oil, it’s because they’ve replaced it with palm oil which is naturally saturated and has the same consistency as lard or hydrogenated oil. I doubt you would fool the grandkids if you made the filling with regular liquid vegetable oil. I suspect it wouldn’t have the right creamy texture.