I don't believe there is a model that would have been an LH29, Demon's were only LL29's or LM29's as far as I know. I could be wrong, but I don't recall seeing a "h" price class Demon, even the 340 cars were "m".
Yeah but only for '71 and '72. A '73 Dodge Dart Sport would have the "L" and the "29" too, just a 3 for the year code.
And as far as I know, only L or M for price class.