Vintage Art Deco Genuine Gray Blue Pearl Necklace

Art deco akoya pearl necklace. Pearls are phenomenal with luster like I've never seen. Pearls are 4-6mm. They have makers marks on the gold rondelles but I cannot make it out. I was told it's an old Boucheron from the 1920's. Costs $1000 to authenticate it at Boucheron when I contacted them. A real showstopper 16". I'm open to offers.