Briefly, here's a list of the guns shown, starting at the end of the row closest to the museum and ending at end closest to the river:
Early (ca. 1800) 12 pdr. iron gun, banded by Rebs
Brit 32 pdr. naval gun, unbanded, with Blakely pattern rifling
USN 32 pdr, naval M1846, banded by Rebs
Army 32 pdr. seacoast M1829, banded and rifled by Rebs
Blakely 7.5 in. rifle, banded