I'd vote against the "advertising" terms because they don't have a consistent meaning. "Acier diamant", for example, means different things to different makers. Usually, I think, an attempt to assign superior quality . . . or at least better quality steel than for an entry-level gun. But note that for V-C in the above catalog page, "acier diamant" isn't the same depending on the type of barrel in question.

A couple more terms:
Chevrotines--buckshot.
Chromage--chromed bores.