No straightforward answer on this as there were variations (extracted from Rawkins):
Known Individual Regimental Trumpeter's Uniforms
Kürassier-regiment Nr 1
Unsigned print in the Erik Karlsen Smythe collection
1800-1804 Scarlet coat with white facings on the collar, cuffs and turnbacks and scarlet turnbacks with white
trim. White lace edging to the collar, cuffs and lapels. Buttons of white metal. Bicorn hat with white lace trim and tall scarlet feather plume.
Dragoner-Regiment Nr 1 & Dragoner-Regiment Nr 2
After Hoffmann
1804-1811 Scarlet coat with white facings on the collar, cuffs and turnbacks and scarlet turnbacks with white
trim. White or yellow lace edging to the collar, cuffs and lapels. Buttons of regimental colour.
Chevauxleger ‘König'
J Cantler & J A Drexler
1806-1811 Trailing red horsehair plume on the raupenhelm.
Poppy-red coat with dark green collar, lapels and
cuffs and poppy-red turnbacks edged poppy-red.
White lace edging to collar, cuffs and cuff-flaps,
white metal scaled epaulettes 1804-1810.
Chevauxleger ‘König'
H Boisselier & Rene North
1811-1813 Tall scarlet feather plume on raupenhelm. Dark
green coat with poppy-red collar, cuffs, turnbacks and lapels. Silver lace trim to the collar, lapels and upper edges of the cuffs. Scaled contraepaulettes.
Chevauxleger ‘Bubenhofen'
J A Drexler & Wolf Graf, Hoffmann
1807 White feather plume to raupenhelm. Red coat with black collar and cuffs and turnbacks piped red. Red lapels with three rows of eight buttons each with a white twisted braid galon. White fringed epaulettes. The collar trimmed at the top and leading edges with gold lace (possibly the
korporal-trompet).
1812-1814
1812: Red coat with black collar, cuffs, cuff flaps and turnbacks piped red, collar, cuffs and lapels edged with white lace. White fringed epaulettes. Also shown with bicorn hat, light blue coat faced black with white lace and white metal contra-epaulettes in 1814 by Hoffmann and erroneously labelled as Regiment Nr 4 by Drexler.
Chevauxleger ‘Minucci'
H Boisselier & Rene North
1811-1813 Red trailing horsehair plume. Scarlet coat with
dark green collar, cuffs, cuff-flaps, lapels and turnbacks all trimmed with white edging. Dark green ‘wing' dummy sleeves at the rear of the coat edged white. White full fringed epaulettes
Chevauxleger ‘Prinz Taxis'
H Boisselier
1811-1813 Red trailing horsehair plume. Scarlet coat with
white collar, cuffs, cuff-flaps, lapels and turnbacks
all trimmed with yellow edging. White ‘wing' dummy sleeves at the rear of the coat edged yellow. White full fringed epaulettes
Chevauxleger ‘Kronprinz'
H Boisselier & J A Drexler
1811-1813 Red trailing horsehair plume. Cornflower blue coat
with black collar, cuffs, lapels and turnbacks all trimmed with white edging. Cornflower blue cuff flaps. Black ‘wing' dummy sleeves at the rear of the coat edged white. White full fringed epaulettes.
Boisselier planche