My understanding is that the only Noilly Prat dry vermouth available in the United States from roughly 1945 until approximately 2007/2008 was the Extra Dry formula. (The latter approximation pertains to the vagaries of distribution.) This Extra Dry formula is what that NP developed exclusively for the American market in order to better compete against lighter, paler vermouth styles that were then taking over the US vermouth market, and this was the formula NP was known for in this country during those subsequent five decades.
Around 2008, Noilly Prat attempted to summarily discontinue the Extra Dry formula and replace it with the Original Dry formula, which is what they sold in pretty much all other markets. They made no attempt to choreograph or re-introduce the Original Dry. The switcheroo was a catastrophe: American Martini drinkers did not like the different Original Dry formula and wanted the Extra Dry formula they were used to. Eric Seed was right there with Dolin Dry Vermouth to gobble whatever was left of NP’s market share, and the rest is history. Noilly Prat eventually realized their mistake and put their Extra Dry back into production, returning it to the American market around 2011/2012, but the damage was already done. Meanwhile, they’ve done little to address the confusion.
Personally, I want to like NP Original Dry, but I just don’t; and I sure tried when it showed up, convinced that the European formula must be better by default. I’d rather use Extra Dry. Actually, I’ll stick with Dolin. (That said, NP Original Dry is certainly what I’d choose for cooking, not that I cook Marseilles cuisine much.)