Miller,

I went over it again.

-- 12 over C in a diamond was used from 1898 to 1924.
-- They stopped using decimals for the barrel weight in 1924.
-- The Crown over PV was not used until 1959.

Doing these by description only is always interesting. I believe you are correct about it being originally nitro proofed. Especially since it was done for a French company.

Pete