Hi greasemonkey i was just searching model B on here and noticed that your's is 18 gun's later off the production line than mine.
My mod B is number 16918.
It seems to have a slot cut into the trigger block for a diopter sight, unfortunately I've yet to find a replacement.
It's a bit rough on the outside but lovely to shoot, always the rifle i reach for when plinking.
Anyway this is my first attempt at adding a photo on here so could go wrong.