benelli barrel

found a benelli barrel at a storage auction, looks new, reminds me of a m-1 super 90 barrel, it is for a semi auto, has the rifle sights on it, 19 1/2 in to end of chamber and 24 in total length, how can i tell if its for a m-1 super 90 or a m-2 or m-2 or m-3 or are they all the same, thanks