"Fanfaren-Fähnlein"? Mmm.. The "Fanfaren-Fähnlein" isn't shown in the regulations around the time when this letter was ostensibly produced1,2 The official designation for the DJ units that carried the Fanfare and Landsknechtstrommel was "DJ-Fanfarenzug" and the permitted strengths of these were: 1(FZ-Führer):18 (players), 1:24, 1:36, 1:48 and 1:60 (with the ratio of fanfares to drums being 2:1). Regardless of their size, the designation for these formations is always given as "DJ-Fanfarenzug".
Having said all of the above, the letter (which isn't a "presentation" letter) seems genuine enough and it does have "Fanfaren-Fähnlein" at top left so the possibility that this musical formation was authorised for this particular Bann can't be dismissed. It doesn't make logical sense to me personally that there would have been a requirement for a "Fanfaren-Fähnlein" but that's just one opinion.
1 Aufbau und Gliederung der Spieleinheiten der Hitler Jugend (Spieleinheitenordnung)
2 Der Dienst in den Musikeinheiten der Hitler Jugend 1.10.1941