G'day, new guy here. Doing a general Google search on the above rifle leads me repeatedly to here so I registered and now you're stuck with me.

After registration, I did conduct a search where I found out quite a bit on the calibre itself but not much on the rifle. I was hoping to see what other nuggets of information might be supplied.
The barrel is marked as in the topic title...'Sauer & Sohn' out on the barrel and calibre over the breech in a 'box'.
The breech is marked on the side with a Crown over B, next to a Crown over G, both above a Crown over U. Underneath that is, what I have come to learn from here, the gauge marking (right?) of 108/49.
The frame is marked with an identical Crown over B atop a Crown over U.
The only other marks I can find are a serial number on the lower tang behind the triggers, same s/n on the barrel lug, barrel shank and the flat where the frame meets the barrel.
There is one other mark on the bottom of the barrel which I cannot quite decipher...need better light and a 'glass. There are other 'indents' which may only be scars from use but, again, the glass and light...
I can likely put up some photos in a bit, utilizing my 'kitchen table studio', if that will help.
Any other marks I should look for?
What can you tell me about this little rifle?
Thank you,
Hoot