Dont stop at the first line of the Code.
43 U.S. Code Chapter 39 - ABANDONED SHIPWRECKS
(a) the term “embedded” means firmly affixed in the submerged lands or in coralline formations such that the use of tools of excavation is required in order to move the bottom sediments to gain access to the shipwreck, its cargo, and any part thereof;
43 U.S. Code § 2105 - Rights of ownership
(a) United States title
The United States asserts title to any abandoned shipwreck that is—
(1) embedded in submerged lands of a State;
(2) embedded in coralline formations protected by a State on submerged lands of a State; or
(3) on submerged lands of a State and is included in or determined eligible for inclusion in the National Register.
Note that section(2) states OR and simply refers to submerged lands, which this appears to be.
(c) Transfer of title to States
The title of the United States to any abandoned shipwreck asserted under subsection (a) of this section is transferred to the State in or on whose submerged lands the shipwreck is located.
Looking at the Code, there are 3 criteria, embedded is but one, coraline encrusted is another, OR in submerged lands. It would be very difficult to prove a cannon on the bottom is not embedded, nor encrusted, and really, really difficult to prove it is not submerged.
These days, it is also unlikely that a shipwreck item cannot be proven, especially cannon. If that argument was valid, every shipwreck salvage team would claim unidentified. As we have seen with Odyssey, that doesnt work and gets you Contempt of Court charges, penalties, and confiscation of the recovery.
In addition, without provenance, the artifacts are worth little more than scrap, so if you want value, you need identification, thus the catch22. You have already stated that the stone was removed from the fort, and that would have been by the Spanish. BUT, there is documentation that monuments went back to France. The cannon are the key, that marking on them certainly are not AC/DC props! The video shows enough information to id the cannon for certain.
Not embedded?!?!
Anything else you forgot to share?
"It was first believed these items were from Ribault's two 'lost ships' that were destroyed in 1565 by a storm, Prichett told LiveScience.
However, after reviewing records, Prichett and his team discovered that the bronze cannons and marble monument were not aboard Ribault's ships, but were station at an early French Huguenot colony in Fort Caroline, which is now Jacksonville, Florida.
After digging even further, the team learned the four items were stolen during a Spanish raid in 1565.
Pritchett believes the pieces were headed to Havana, Cuba when the three Spanish ships were met by a storm out at sea that sank the vessels."
16th centurySpanish shipwrecks found off Cape Canaveral filled with stolen French treasure | Daily Mail Online
With Goold on point, be it France or Spain, you need to make the call.