Hi Don,
This gun is very early 20th century, as it is proved for both "Poudre S" and "T". Certainly made pre-WWI.
The EP is a Parisian proof mark.
I don't know who "CG" was, and even tough it says monobloc, I don't say any evidence of a sleeved construction.
Could you please post a close-in of the proof marks on the barrels? and of any other marking?

That would greatly help.
Best regards,
WC-