Thanks Dan. I usually come in through the "new posts" link and I forget that people read by category...
If that's the catalog at collection-appareils.fr, it's the same one I was looking at. I don't have the set at hand, but it has a serial number somewhere on it---a rigorous few minutes with Google suggested that the number was from the very late thirties, IIRC. The labelling is SOM Berthiot, the diaphragm is in mm, and the engraving has a sort of clean modern look, with white fill in the lettering.
One other oddity---if you look at that catalog page, it shows the barrel sitting longitudinally in the casket, so that the "pipe" runs left/right as you face the box. Mine doesn't fit that way; to get the barrel into the box, you have to orient it axially, front/back. (I suppose I can't swear on my mother's grave that it's the original box, not least because she's still alive and might object, but it *looks* like the one in the catalog.) So *something* is different.
(Why isn't the 180mm combination f/7.1? The 305mm cell should have a 25.2mm aperture, and 180/25.2 is about 7.14. Mutatis mutandis for the other combinations. I have the feeling the answer is obvious.)
-NT