They *might* have promoted the format during ad breaks on the station, but such a format is utterly incompatible with WNCX's main audience. Which of course has been carefully preserved in amber since 1989.
If anything, HD radio is usually advertised on CC and CBS radio stations far too much - once every hour, on every station (both are key subsidizers of the iBiquity standard). IIRC, they aren't even advertisements, but usually run as PSAs... neither CC or CBS profits out of airing them.