According to the 1860 census, NOLA was #6 with 168,675 and St Louis #8 at 160,773 but frankly, that is a minor quibble. The issue of St. Louis being able to produce things while not under Federal control is questionable. St. Louis was a bustling ship building center but where did the materials to fabricate these vessels originate from? Where did she get her iron? I can't find one Phoenix Iron Works-esque establishment in Missouri. (If someone else can, please post - my google-fu seems to be off on this topic). Without the iron, no ironclads. No armor, no engines, no armament...I believe her metals stock came from other Union States.
Cheers,
USS ALASKA