I am installing a new Ideal Steel wood stove in an existing (inside) chimney that has 13" x 13" clay flue. I am trying to find out if the Class A chimney pipe that I already own meets UL 103 HT. Please see the attached image of the label on the pipe. I have tried to find out what "listed 257J" means but haven't had any luck. The stove pipe is probably at least 12 years old and is in perfect condition. Thanks you for any information you can tell me about it.