Robert,

Just a possibility: Brig. Gen. William Nelson Pendleton, Chief of Artillery at Centreville, had been trying all fall and winter of 1861 to increase the number of guns in General Joseph Jonston’s army at Centreville, Va. The army in Northern Virginia was woefully short on guns, not only in Centreville, but at Leesburg, Va. and on the Blockade of the Potomac River. Pendleton had gone to Richmond a number of times to lobby the government authorities for more guns, and he had also gone to the Tredegar Works to have them build new cannon for him. He was very succefful in that he increased the number of guns at Centreville from 71 in November 1861, to 175 by February 1862. Johnston had repeatedly asked Davis and other officials to transfer weapons and men from other commands to the army at Centreville.

The Union guns that were captured after the Battle of First Manassas were all sent to Richmond for re-distribution. At the same time, Tredegar was taking all of the old smoothbore guns (Confederate and Union) and rifling them, before sending them back to the front. The smoothbores you mentioned may have ended up in Richmond and then went to Johnston’s army.

Just a possibility.