Sorry for this late reply on your great effort Raimey.
I've been offline for some time. I have been looking for the St stamp on other Ferlach guns, but so far, I can't find other gunmakers using this stamp. In my opinion, it's another piece in this pussle, telling me that the gun probably is made by Sigott.
Please tell me if you think I rush to the conclusion. :-)

Regards Joar.