Not sure about Bonefishing - I know in the Bahamas you are allowed to fish from a dock or beach. However, their are limits and restrictions on fishing if it's being done from a boat. Those tend to be on shellfish, pelagic species, turtles etc.. I would recommend that you just check with a local marine officer once you arrive.
They've just passed a law here in Belize to attempt to force all tourist to take a local guide if they wish to fish. It's pretty steep for punishment. But then again like many things in Belize their just aren't any man power to enforce the law.
Best of luck and enjoy the fishing.
Jim "Big D" Harper
Bite Me Belize