That's correct. You have a somewhat-rare Huret dropout with a "front" and "rear" stop. By contrast, the much-more-common Campy-style dropout has only a "front" stop. I don't know if I ever saw a successful "normal" derailleur installation on the oddball Huret dropout- the "B" screw needs to be extra-extra long and bent around to contact the stop.

I do remember that the Huret Duopar had an interchangeable stop on the main pivot bolt. One version worked with the "Campy" style derailleur hanger, the other worked with the "Huret" style.

Geez- that's from the really dusty parts of my bike parts memories.