Ole, I think the AT Thompson imported ones are Darlot. I have a similar magic lantern lens but it's more like 15" f4. I've resisted the temptation to put an aperture in because it's one less decision to make. If I use that lens it will definitely be a head with extremely shallow depth.
At least your lens has a slot to put stops in. Mine marked A.T. Thompson importers doesn't even have that.