Parfums D'Orsay reformulated in the 1990s and then again recently. The boxes were also changed along with the logo, supposedly a coat of arms. (Coats of arms can't be "reworked" as there are strict rules of heraldry. The coronet--the count's 'crown'--was changed with the new packaging.)
For the record, the company was founded in 1908 and not 1830 as on the boxes. The fanciful tale of the namesake being a perfumer is a pure marketing fabrication.
You can read more here on the marketing and history:
Nigel Groom, 2nd ed. "The Perfume Handbook."
Ken Leach. "Perfume Presentations."
Madeline Marsh. "Miller's Perfume Bottles: A Collector's Guide."
For the record, Parfums D'Orsay sued Guerlain for the use of the word "dandy." Guerlain, the company with the real history, was obliged to pull its Arsene Lupin Dandy bottles and repackage.
Olivia Giacobetti's Tillieul is still the best of the lot.
Le Dandy EDT (in the old white boxes), once so wonderful, is now reformulated without the oakmoss in a new EDP version. Not the same at all. Something is missing, and it's not helpful.
Chevalier is a good spicy floral. I can't say about the new version.
If you come across the older bottles (striped, usually), I would buy them.