Is this a prototype or another model, we don't know...
UPDATED
The recent documentary on the history of the submarine 'La Minerve' shows the radio room equipments including this receiver. It is also perfectly identifiable on a photo of the Daphne-class S650 'Flore' published on Wikipedia with, next to it, a SAGEM SPE5.
It therefore appears that this equipment really existed at the same time as the TRC361 version.
It is possible that this format was reserved for submarines, the other format for surface ships.
One can notice that the RM-BT-3A VLF/HF shift converter, which can also be seen in the Flore radio room, is exactly the same format.
I think my equipment is either a prototype or has been used as a troubleshooting bench.
Unfortunately, I could not restart it given the state of certain cards and the absence of other cards. What a pity.
