George, have you checked the underside of your forend wood? Beretta model numbers were often marked there. The OLD Silver Hawks from the 50's and 60's, which were in fact 409's with some adjustments for the American market, are usually stamped "409" in the forend wood.
Larry I looked long and hard at the forend on my model 410 and there are no numbers stamped in the wood, unless they're under the forend iron. Come to think of it, I had the iron off a couple of weeks ago messing with a sticky ejector and there were no numbers under there either.
SMLE, the steel is the same as Roy's, "Titania"...Geo