if it's a masquelier gun, it should have his mark, which is a stylized "mask"....somewhat triangular in shape if my memory is correct...should be on the water table....please give a shot of the flats.

looks like there are two different numbers on the tubes....right tube looks like 35705, and left tube is easier to read at 35786 - those may be tube numbers, not serial numbers. also see 654 stamped rather lightly on the right barrel flat...is that the serial #?

as docdrew observes, there is no lettre annale....so it's pre 1922.

best regards,