I have a Shure Brothers Model DY40 microphone. Other than it's brushed nickle chrome finish, it's shape and "grille" is very much like the Bullet series. If I didn't believe the "Shure Brothers" metal tag on the microphone stamped with the DY40 model number, I would say it doesn't exist. Is there any archived information on this microphone?
DY40 - This would be a Shure mic that was packaged with some other product, such as a tape recorder or two-way radio, and sold as a package by the maker of the other product. The DY40 is equal to the 540.