Correct, véritable Opale is a label used by (IVV?) in the Florence region. Véritable is French, not Italian - but a lot of 'opale' and 'opaline' was made for export to France. You are bound to run into pieces with those labels in any French market.
There may be some confusion between French and Italian, though. Opale is a solid semi translucent colour, Opalina (Italian) is opale cased in cristallo (clear).