I would think it probably isn't. In older homes with ceiling popcorn paint they would mix the two, but I would doubt the closet from what you are saying, but only a test would show for sure. Even then with the popcorn paint they would mix in a horse's hair and that, sometimes would scare people, too. Pittsburgh is noted for older homes and there's alot of places you can call and have it checked beforehand. A restoration service can be recommended through your homeowners. My homeowners paid for me to have it done.