Landstrom Grapes & Leaves 10k Black Hills Gold Stick Pin

This grape & leaves 10k solid yellow rose gold lapel Black Hills Landstrom stick pin / pin is in excellent vintage condition. Maker's mark L for Landstrom. The leaves top part is 10k gold marked 10k. The shank needle part is marked - Gold filled. The pin weighs - 1.66 grams & measures approx. - 2 5/8 x 5/8 inches.
I believe it was produced in the 1960's/1970's.