As far as I'm aware, Honda did not offer side window louvers as an official accessory for the 2016-2019 Honda Civic Sedan. However, there are aftermarket options available from various manufacturers that may fit your vehicle. You can check with automotive parts retailers or online marketplaces to find these products. It's important to note that aftermarket products may not have the same fit and quality as official accessories, so it's important to do your research and read reviews before purchasing. Additionally, adding aftermarket accessories may affect your vehicle's warranty or insurance coverage, so it's always a good idea to check with your dealership or insurance provider before making modifications.