I have seen them on eBay but maybe only a couple in 10 years or more. They were not overly priced. You may not have many options on your gun for a rear sight. While the sight is rare, most likely demand for the sight is rare as well. I am away from home now but at the a Louisville gun show, a dealer named sight man, sold all kinds of sights. If your OMS is a 38, it’s maybe a $5-600 gun so you would have to decide if it’s worth it.