Yes, proof marks are specific by country.
Typically the scenario would be a Belgian gun to a finisher or dealer in France or Germany.
I don't know when France required re-proof - 1897 or 1923 (Ted will know)
I don't know when Germany required re-proof - ? 1893 (Raimey will know)
The Belgian gun would carry full proof marks including the 3rd Definitive Proof mark.

I don't know the rules when U.S. gunmakers imported un-finished actions from Belgium. The barrels would have to carry Provisional Proof which was an intertwined script EL

An example with post-1923 French marks and post-1924 Belgian - the omega with the chamber length and the crowned ELG are the Definitive Marks. The fused AC is the Belgian inspector's mark.
There would be more marks on the barrels just forward of the flats.

[Linked Image from photos.smugmug.com]

That all changed with CIP member nations accepting the proof of other CIP members.

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