its "the right stuff" (thats the name of it) Permatex gasket maker & not needed for the exhaust manifold gasket (& it sure ain't cheap). your other corners are fine, Take care of this one & you're set. Do you have the stud out?
Yes-stud is out and looks perfectly fine!
So could I go with the pipe sealant (500 deg range) or Red Hi Temp RTV that I have on hand or do I need to go with something more, like Copper Ultra temp RTV or Right Stuff?
Right Stuff was like $20 for a tube and I only need a pinch. I'll get it if I have to though.