Possible dumb question: does the 2 3/4" marking indicate that this gun was rechambered from 2 1/2" or was Francotte chambering this length (for export?) so early?

I've come to "expect" that Continental guns of this vintage were originally chambered for the shorter shells. (I realize one can "expect" ANYTHING in the world of doubles, especially in that era when "custom" was normal.....).