This is what I have.
From the a pamphlet published by Raider Games in 1987. It's called "The Wurttemburg Army 1793 – 1815" by G.F.Nafziger.
"In March ( this would be 1808 ) the fifth squadron of the Chevauxleger Regiment Herzog Heinrich and the fourth squadron of Leib-Chevauleger were taken to form the third and fourth Garde-du-Corp squadrons. In addition, the Garde-du-Corps was increased by the raising of two new squadrons, bring its total strength to three squadrons. One squadron was drawn the Cheavauxleger-Regiment Herzog Heonrich and one from the Lieb-Chevaxleger Regiment. Both squadrons became "grenadiers". The Guard formation was then titled the "Garde-Regiment zu Pferd". In June the Leibjager Squadron was incorporated into the regiment. The Garde-Regiment zu Pferd now consisted of:
1st Squadron---------Leibjager ( 130 men & Garde Gendarmarie )
2nd ( Leib ) Squadron--Garde-du-Corps ( 127 men )
3rd & 4th Squadrons--Grenadiers ( 126 men each )
Despite these designations, when the regiment campaigned all four went as grenadiers. Their uniforms were slightly different, however. The 1st squadron wore a green coat and the others wore blue coats. Each squadron rode a distinctively coloured horse, different in color from those ridden by the other squadrons."
That is taken from the pamphlet. It does not say the colour of the horses. I know Napoleon did the same thing with his cavalry regiments. "In 1810 the horses of Guard Lighthorse-Lancers were between 14 1/4 and 14 1/2 hands tall in "uniform groups of chestnuts, bay, black and dark grey." That's from this website under French Guard Cavalry ( napoleonistyka.atspace.com ) .
The only resource I have with coloured prints is "Arms and Uniforms The Napoleonic Wars" Part one & two By Liliane and Fred Funcken, but I have found them very unreliable. So I will leave that to someone else to offer up. Hope this helps. Not sure that it gives you what you want.
The Wurttemburg Army is beautiful, with their helmets and dark blue uniforms they look grand on the gaming table.