Looks like they either conferred with or watched postings on LS forums, took some of the good ideas and incorporated it in their offering. Don't know who's idea the sound was, but could have made the chuff better by using the sensor on the tender axle like they did on the Pacific. At the time of its introduction I wasn't interested in a 'plastic' live steam loco, time changes things.
I don't think anyone has discovered this, but we are all pretty sure it was not Kader / Sanda Kan, their normal supplier. We believe it was a korean company, from the electronics, but of course the loco and the electronics could be from 2 different places.
Navin might know, if you have a relationship with him.