The two musketeer battalions are fielded as the Yaroslavl Musketeer Regiment with the contribution of the Yaroslavl grenadier companies towards the combined grenadier battalion.
The combined grenadier battalion is composed of grenadier companies from Yaroslavl Musketeer Regiment and the Astrakhan Grenadier Regiment. Keep in mind that during this early period, Russian grenadier regiments wore the short mitre for the fusiliers while the grenadiers wore the tall mitre. That reminds me that I need to order Russian fusiliers now to field the two fusilier battalions of Astrakhan Grenadier Regiment.
Notice that the combined grenadier battalion maintains distinctive facings and mitre backs for each of the two contributing parent regiments.