They didn't make too many of those carbs with the needle valve built in, they went to the remote needle valve pretty quickly instead.
Sometimes on that big auction site you can find the parts to put together a OS 8 carb with needle valve, but they usually price the parts accordingly though. Another idea is to get a ASP 1.80 carburetor. The ASP carb should bolt right up to a OS BGX OK. That huge Hong Kong based hobby shop sells the ASP engines and parts. But sometimes they have them on back order though.