Thank you, I have seen the A & B grades listed as starting in 1890, 1892 and 1897 so good to have the correct range. Do the model A's and B's have a separate serial number series or were they combined? I have two Model A's serial number 591 and 4331. The low number has more engraving then the higher one, but I guess engraving details changed over time. As for the DGJ article of 2003 Winter, i am at work at the moment and will provide the author's names when I get home later. thanks for your help.Matt