I'm allowed to pick up and bring in all the porcelin pieces I find. I have been told once to leave metal and other stuff alone unless it's really interesting. They are trying to get a surf debris pattern for the "good" porcelin off a Spanish trade vessel in the area I go to so they can eventually pursue it.
There is sadly a lot of burned out porcelin from the wreck that all the glaze and markings have been worn off of, maybe 70% of it. There are also a lot of other vessels wrecked in the same general area. I photograph most of the stuff I see and I may move things up the beach to a dune line to see if they want to recover them, or rebury stuff found away from the surf line.