The American Civil War Research Database, Historical Data Systems, Inc. was only able to document one individual who was killed at Petersburg, April 2, 1865. Not surprising as the last muster rolls on record are for the bi-monthly period, Sept & Oct, 1864

Alphonso Meadows
Residence Lowndes County AL;
Enlisted as a Private
"H" Co. AL 3rd Infantry

Placed in the trenches at Petersburg, the Third dwindled away by attrition till only about 40 laid down their arms at Appomattox.
http://www.rootsweb.ancestry.com/~alcwroot/infantry_files/3rd_ala_inf.htm

April 9, 1865
Surrendered 9 officers and 93 men at Appomattox under the command of Captain Cornelius Robinson, Jr.
http://www.civilwarintheeast.com/CSA/AL/3AL.php

Of interest, this is the only reference to the regiment in the Official Records for this period.

HEADQUARTERS FIFTH ARMY CORPS,
March 5, 1865.

Col. G. D. RUGGLES,
Assistant Adjutant-General:

I have the honor to report that three deserters have just come in; names: John Artwell, J. D. Munn, D. B. Locklar, all of Third Alabama Infantry, Gordon's corps, Grimes' division. They left the rebel line about 4.30 this morning. These men were ordered to be in readiness to move at 5 o'clock this morning in case of an emergency. They know of no movements of troops. It is reported that General Lee has gone to North Carolina. They think Johnston commands in his absence., but they are not certain. These men have been sent to headquarters Army of the Potomac.

Respectfully,

G. K. WARREN,
Major-General of Volunteers.
OR V 46, Pt. 2, p. 844