There'd be no way in hades I'd get a new Offenhauser valve cover. They're poor quality at best now. I'd look for an older run and buy a used one. @CudaChick1968 can tell you all about the new ones. And I sure as HECK wouldn't pay THAT for one.
I'm not going to pay that much either. What I really want is an old style factory cover with the pressed in ribs like the one in post #9. Paint it with black wrinkle coat and it will look great on the engine (either yellow or red, haven't decided).