Jon - Gunter is completely correct; the 'break' date in terms of regimental reorganisation comes on 12 October 1810. Prior to that date, all Musketeer Regiments were composed of 1 x Grenadier + 2 x Musketeer battalions (each battalion being 4 companies of the same 'type' of infantry).
After the break date, all Musketeer regiments were composed of 3 x Musketeer battalions, each battalion containing 1 x Grenadier company (1platoon Grenadiers, 1xplatoon Tirailleurs), + 3 x Musketeer companies.
It's all in Mark Conrad's tranlsation of Vikovatov: http://marksrussianmilitaryhistory.info ... estore.htm
Hope that helps.