Today has been a nice and warm day so I have removed the manifold. I have redrilled the threads except the one that broke - flush - as it has turned out. As mentioned, I planned to install another exhaust manifold leaving the broken bolt since it hadn’t been used when the engine hab been assembled. BUT - the surface of the cylinder head looks bad ... at least to me. I’ve attached a picture ... does it have to be removed and resurfaced?