The correct serial number is 6469m. It's what is often called a 1920 Commercial or an "alphabet Luger." Being an "m" block , it was probably made in 1922/1923. It should be .30 Luger (7.65x21mm), not 9mm (9x19mm) For what it's worth, the .30 Luger is really sweet shooting cartridge - you'll like it.