"Umriß einer pragmatischen Geschichte des Kriegswesens im Herzogthum Braunschweig" by Carl Venturini has (apologies as it is possible I might not have noted down the fraktur script correctly):
"Nach den Bernichtungs-Schlachten von Jena und Auerstadt 1806, entlus sich die Wetterwolte auch uber Braunschweigs Gesilde. Das die Truppen friedlich in der heimath geblieben, und seinen thatigen Antheil an dem kriege genommen hatten, auch gar seine Bortebrungen dazu getrossen worden waren; dass wesber die Beurlaubten einberusen, noch die pferde des Dragoner-Regiments vollzahlig gemacht wurden."
which very roughly translates as – though the second sentence does not seem quite right as surely it should be "…taken no active" rather the wording below:
"After the battles of Jena and Auerstadt in 1806, the storm clouds also gathered over Brunswick's population. That the troops had remained peacefully in their homeland and had taken an active part in the war, and that their contributions had been accounted for; that neither the furloughed soldiers were being recalled, nor were the horses of the Dragoon Regiment fully accounted for."
Also from the above book the 1806 army was larger than Nafziger's booklet led me to believe. Revised OoB:
Dragoner-Regiment von Klosterlein
Warnstedt Infanterie-Regiment
Griesheim Infanterie-Regiment
Garnison-Bataillon
Land-Regiment
Artillerie & Ingenieur Corps
Friedrich Schirmer & Paul Ferdinand Koch drawings:
Officer Griesheim Infanterie-Regiment 1806 link
Grenadier Griesheim Infanterie-Regiment 1806 link
Zimmermann Warnstedt Infanterie-Regiment link
Although there were two regiments with the Prussian Army with the title "Braunschweig-Oels" and "Braunschweig-Luneburg" – they were not Brunswick Regiments but Prussian Regiments named after their inhaber (Colonel-in-Chief)