Is Metal Detecting allowed: No, unless you are a professional Archeologist.
Excerpt from Cultural Resources. You can find the regulations HERE:
No person shall excavate, dig into, remove from, take, or alter a state archaeological landmark or any other archaeological site on state-owned lands except pursuant to and in accordance with the terms and provisions of a contract for survey and salvage.
I also found a metal detector permit for the Army Corp of Engineers. HERE. Excerpt from permit below.
The use of metal detectors will be allowed on beaches or other previously disturbed areas that do not contain or would not reasonably be expected to contain archeological, historical, or paleontological resources. The use of metal detectors around occupied campsites is PROHIBITED!
FMDAC Disclaimer: FMDAC assumes no responsibility for any person who knowingly or accidentally violates any state park regulation. Although FMDAC will try to keep this information current we cannot anticipate how each regulation will be interpreted by a specific park department, park employee or other government employee. It is the sole responsibility of each individual to know and obey the regulations of the park or area they are visiting and or metal detecting.