When in doubt....Google it.Come to find out, this was a fairly big chain during the 60s in the New England area which was started by William Rosenberg who also founded Dunkin Donuts. White I remember Burger Chef more than Howdy Beefburgers, there appears to be at least one of the franchises located here in RI. http://www.library.unh.edu/special/index.php/william-rosenberg>Here's what they looked like (this is not the RI Howdy):As far as not being "Vintage enough", there's a lot here on the memorabilia side that is much later than "pre-war" so thanks for posting this neat piece. Personally, I love any type of product advertising before the seventies so thanks for sharing. Of course, if it was a Yankees piece and not a Red Sox piece, I would think otherwise! Greg