There was a journal article on an excavation of the gunboat CSS Arrow. She was burned and scuttled up Pearl River. Much of her machinery was salvaged at some point, and her armament was not found, though misc shells were. She was contemporary with the Oregon and it was apparent that in the case of the Arrow that minimal structural changes had been made of the vessel. Let me check through my files, I know I have a copy of that Journal issue. It included a conjectural drawing of the Arrow based upon measurements of the wreck.