1955/ Jan. Early Burbank…..with Chicago parts (made sense for the first couple years of transition). The M is missing or never made the stamp embossing properly. It measures an ML. 460. It was a custom, as it has an added 3rd valve slide water key. All else is normal. The silver plate is 100% intact. A full valve job was done within the last year. Great player……. Comes with a protective WolfPac Single case.