(Helen) I need to do some research into these Armstrong models. The non-Heritage horns have a bit of a unknown pedigree. It has been suggested that they were indeed made by Keilwerth; or that they were reversed engineered by Armstrong in the USA; or that they came in pieces from Germany and assembled and finished in the USA at the Armstrong plant. 

Jury is out, but comparing the non-Heritage to the Heritage series of horns, you most defitiely can see a difference.