Almost certainly; glass decorating, refining, as it's called, is often a separate thing altogether. Sometimes it's done in-house by the glass manufacturer, sometimes it's sub-contracted out by the manufacturer, and sometimes glass is bought in by the refiner (and possibly other variations). In this case, the Orsellys were/are almost certainly glass refiners who bought in glass to decorate and sell on; otherwise the glass woudn't be sold as "decorated by", more likely as simply "made by".
What puzzles me is why we have a label intact but no decoration. A stuck-on label in good condition usually implies dusting but little washing or use. A tie-on label in good condition would imply dusting but no washing or use - you simply wouldn't keep taking it off and putting it back on - so where did the decoration go? It would have to be pretty shoddy to disappear with dusting. OR maybe the label came from elsewhere. Labels are mobile, unfortunately. The archaic French is just a marketing affectation I suspect rather than a clue.
Try a picture against a black ground with and without flash. That may help to highlight any markings. Did you look on the bottom for an etched or engraved mark? How much wear is there on the bottom?