It wasn't said that the Géophysic came with a 9 cts Case, but it is said that 2500 movements were made.
When you number all the Geophysics made, you reach a bit more than 1400, all metals and references included.
So, there is a gap, and yours may fit the gap.
I'm intrigued!
How is the shape of your buckle, by the way...
A JL Logo applied on it at the middel of the buckle?
Best,
nicolas