Vintage Gold Filled Tri Colored Leaves Heavy Link Chain Necklace Black Hills? ETC9048

This is a vintage gold filled chain necklace. It features tri-colored gold leaves on both ends of the links. Some of the leaves are a solid color while others are multi-colored. There are 9 missing leaves on the necklace, mostly at the top toward the clasp. The clasp is marked W & SP. I cannot find this mark in the database, so it could be Black Hills, but I cannot be positive. The chain is 18" long x 5/16" wide. Total weight is 34.1 grams.
This is a vintage, previously owned necklace. Therefore, light wear can be expected.