The little bug (SB&Co) shows up all over the place. I have never heard of SB&Co-G until now. Craig, if you can post pictures I know I would find them interesting. At one time, I believed I had this figured out. Now, I am only sure that I don't.... I had thought the rhombus was associated with SB&Co. After all of Raimey's digging and questioning, I no longer believe that. Presently I am leaning towards the idea that the rhombus was an exporter / importer mark. The problem is that the more guns that surface with these marks, the harder it is to put it all together. If, as you say there indeed is an SB&Co-G mark, well.... back to square 1 again.

Pete