Of course it doesn't have a rating for it.. They are not marketing it for that purpose. But I can tell you from both using it in a car years ago and seeing others who have done it that it works.
You can believe me or not, but not everyone wants to drop a hundred bucks for a tiny bit of soundproofing for a door kit. How many things are used off label? ****, do you know how many drugs are used for things other than what they are labelled for? I went on a work trip a few years ago and one of the first things that was given to us after we got off the plane was viagra because of thin air!