Barrel markings are hard to read but here's what I have - from rear.
left: BA, 17.0, St Etienne double proof marks then a G with an M over it.

Right: all same except 22.0, no BA here and serial #40**

There are no other markings on the barrels. The flats you can see in the picture.
The underside of the forearm has no markings but the primary screw is engraved and there are traces of case hardening.