I'm looking to find out about the meaning of a number on a Silvertone accordion which was made in Italy. There is a number inscribed just below the Made in Italy. It is 309 96. I believe that the 96 is the number of Bass buttons, but the 309 has me stumped. I thought it might be the number of keys on the keyboard side, but 309 seems to be way too many. Any accordionists out there that can help me out?