It really doesn't matter if that carb is obsolete. The main difference in each model is the size of the jets. My carb is seeping fuel under the accelerator pump. Carbs Unlimited carries BBD jets but no metering rods. Is there any place to obtain metering rods?
I would just try getting the proper carb for your application first. If you want to play with the one you have, try contacting a carburetor shop (if there are of those around anymore). They're bound to have some, or are least a core to get some.