The reference to a Confederate general "Porter" threw me, as I couldn't recall him. But Edward Porter Alexander was one of the South's brightest and best engineers and technicians. I am sure his assessment of C.S. armament after First Bull Run (First Manassas) was correct, but that was the first major battle of the war (July 1861) and the South had not yet gotten its ordnance supply and foreign purchase systems organized. The smooth bore muskets he mentions were probably the Model 1842, which the C.S. seized in considerable numbers from southern depots and arsenals, good weapons, though not the latest rifled models.
Alexander later became the artillery chief for the Army of Northern Virginia. He was one of the first Confederate officers to recognize the value of balloons for observation and actually ascended in one to scout Federal positions. He had a somewhat unique role at Gettysburg, being ordered to fire the cannon shots that would signal Pickett's attack to begin at his discretion and when he judged the best moment. That kind of faith in a subordinate officer was unheard of at the time, and indicated how much trust Lee placed in the young (28 year old) general.