I wonder if this was the outfit that's marked on the butt plate...?

3rd Virginia Volunteer Infantry (1898)

Officers and non-commissioned officers of the regiment, 1898
On 10 March 1898, Nalle was appointed Adjutant General of Virginia; the regiment's Lieutenant Colonel, Warrenton layer Grenville Gaines, was elected Colonel to replace him.[18] The headquarters moved to Warrenton on 12 March 1898. Between 13 and 26 May, the regiment was mustered into Federal service as the 3rd Virginia Volunteer Infantry with 46 officers and 955 enlisted men, one of three Virginia regiments raised for the Spanish–American War in response to the first call for volunteers. Company F of the 1st Regiment of Infantry was mustered in as Company M of the 3rd Virginia.[19] The twelve companies mustered in were: Company A (Danville Grays), Company B (Culpeper Minutemen), Company C (Farmville), Company D (Monticello Guards), Company E (Lynchburg Home Guards), Company F (Alexandria Light Infantry), Company G (Petersburg Grays), Company H (Danville Blues), Company I (Fairfax County), Company K (Washington Guard, Fredericksburg), Company L (Fitz Lee Rifles, Lynchburg), and Company M (Richmond).[20] On 25 May Nalle was appointed Colonel of the regiment, with Gaines resigning simultaneously.[21]

On 5 June the regiment relocated by train to Camp Alger, joining the Second Brigade of the First Division of the Second Army Corps. On 2 August it became part of the newly created Second Brigade of the corps' Third Division alongside the 1st Connecticut Volunteer Infantry.[22][23] At Camp Alger on the night of 8 August, a white hospital steward from the regiment scuffled with a black teamster.[24] A number of men the regiment formed a lynching party, which was turned back. The behavior of the regiment during the incident angered division commander Major General Matthew Butler, a fellow Southerner, into subjecting the regiment to four roll calls a day due to its insubordination.[25]