I know iam nit picking but here it is
the Marines were not Royal until about a year before the battle of Trafalgar of right after so they should just be the British Marines and they serviced in Battalions in the War and there were Grenadiers of the Marines battalion/center company men of the Marines and the New Light Company of the Marines
also being given the name to be a royal regiment/unit that you had "Blue facings aka the color if the collar cuffs and labels of the uniform" not white as the marines did during the war.
also its not just 1st Ferguson Rifles but the name should just stand alone as "Ferguson Rifles" in the unit there were only 100 Ferguson rifles made for military service and the unit only saw action in one battle "King Mountain" were colonel Ferguson was shot and killed thus ending the unit and the advancement on his rifle.
also there were no numbers Germanic units there were only names for the Germanic troops from the many Germanic state such as Hessen-Kassel/Hessen-Hanau/Braunschweig/Anspach-Bayreuth/Waldeck/Anhalt-Zerbst/Hanover and the units were names like these for example Regiment Von Donop Regiment Von Riedesel Regiment Von Rall ex..... the regiment were names after there commander and not a numbers
you can look through this site to find the different regiment name were and when their served and what they looked like during the war before certain alterations were made during there service in the colonies
http://www.vondonop.org/uniformpics.html
