None of my sources mention his adc Galland, you could extend your search through to 1806 as the état-major seems pretty much the same.
There are something like 44 various Galland's in Martinien, but in the cavalerie only 2
sous-lieutenant blessé 3e dragons 20 nov 1805
et
capitaine blessé 16e dragons 5 mai 1812
I checked in Fastes, Quintins Austerlitz (1 cuirassier Galland killed), Bowden, Hortouille.
Maybe mention of him in Foucart (a search in google books?)
I'm sure SHS will know
welcome back chasseur!