CBL1
Can you describe in more detail the markings on the barrels right by the flats in your gun? I have the suspiction that are the same as in my Josef Winkler. Perhaps it is also the local marking for Böhler.
BTW, the barrel-flat emsemble is strinkly the same in my gun as in yours. Mine is one described by Thomas Garwood as entablature lump. Besides it has also one lump crossing the frame and a Greener cross bolt extention.

Regards

EJSXS