I could be wrong, but I'm getting an imitation vibe off these. The baroque pearls seem to repeat shapes and don't have any pits or deep grooves. And the round pearls are all exactly the same shape and size and color, and they match the large baroque pearls in color and luster, which you would not expect if they were real pearls. And I don't see any pearly overtones. Plus, the clasp and end caps are very cheap looking. If those were all real pearls, you would think the clasp would be more expensive with a pearl clasp designed for multi strands of pearls.
How much is the seller asking for the necklace? That will tell a lot about what the seller thinks it is.