I am sorry Richard, that my words made you realize that it was a decisive diagnosis, whereas my approach was more on the 'food for thought' basis.
Still in the mentioned previous thread i submitted that marks depicted by Soler and Lavin are
drawings of punzones whereas all those three in the Armeria Catalogue are images of the
actual thing.
On the other hand, being the discussed barrels of Spanish origin, why the heck should some Frenchy's 'oldest son' punched that inscription underneath ?
Again something (only) to think about, nothing ultimate.
And remember my technical knowledge of (shot)guns is nihil; just trying to stick my nose on marks riddles
.