Never. At least not in my hometown. I drove two hours each way to St. Louis in July to find a couple "living" examples at an all European car show for my restoration research. They must be all hiding out in rust free Colorado. I saw two nice white 230's on my last trip, not the same car I promise. One of them was driving around Old Colorado City and the sound of the engine made me completely jealous. Later, I spotted several more W113's at a Mercedes sales/repair shop. Most were customer cars in an array of colors and one was a personal restoration project. A really nice family owns the shop and they have been in the Mercedes business forever. Whenever I am in Colorado I check in hoping they will have a part I am looking for since they have an all Mercedes parts yard on site as well. They don't really sell hardtop parts though (I needed a back glass). Whenever they get a hardtop they restore and sell it...so if anyone is looking for a complete hardtop Salim's Silver Star Automobiles Service, Inc. in Colorado Springs, CO might be worth a try.
