Hello, I apologize for my English writing through a translator. I want to purchase my first autavia. They offer me an autavia 1163mh, the seller says that this is mk 3 Derek Bell, please help me determine if this model is correct or not. number 142xxx I am confused by the caliber 12, but it is silver, with a broken number. Has such a caliber a rare collection? Should Derek Bell have cal.11 or not? How many such watches are now on the market? Thank.