If you look on my sales site you’ll find a black Swan marked 3162. The /62 code usually refers to the Wine and Silver pattern. Though I haven’t seen it Stephen Hull records that it is sometimes erroneously used for the Almond Green pattern. I always refer to Stephen Hull’s number/pattern chart but I know that there is at least one other list out there: one prepared by members of FPN several years ago.
I searched online and it appears there are or have been other post-war black Swans bearing the number 3162. That means it isn’t just a one-off error as I first thought. It’s hard to imagine why it was thought necessary to apply another number to the simple black pen but it seems that’s what happened.
Might it be that as those mixed colour patterns were no longer produced by 1949 when the pen was made, Mabie Todd decided that the earlier code could be re-used? Even if that is so we still don’t know why it was done.
Stephen Hull: The Swan Pen