It doesn't matter what their policy is, Michigan has preemption, no local unit of government can have any law, rule, or regulation pertaining to firearms or ammunition stricter than the state and the state says you can carry there. See MCL 123.1102 for the relevant law. The courts have also affirmed it twice in MCRGO V. city of Ferndale and MOC V. CADL. So if they give you problems about it you can tell them to go piss up a rope.
Despite knowing that they are preemped many local units of government still have these rules published, hoping on ignorance to gain compliance. In other words they are knowingly and deliberately misleading people, they simply say that a perfectly legal act is in fact illegal or not allowed and fail to mention that they have absolutely zero legal authority to enforce it and that the rule itself is illegal. They know that the average person has no idea about preemption or what the law actually says so that they will see the signs and just comply.
So yes, you can carry there.
In fact if you have a CPL, or whatever your state calls it but choose to open carry you can carry anywhere you want whenever you want save for post offices and federal property, and also the "big 3" campuses do to a quirk in state law.
With a CPL and concealed carry you can still carry there, but avoid schools, hospitals, "entertainment facilities" seating more than 2,500, casinos, churches, and bars, etc. you can find the full list of PFZs online, but Metro Beach is fine.