RF, if you look at the second pic you can see the crack under the #2 exhaust. It starts just above the lower head bolt hole. Then it goes around that corner and stops just below the spark plug hole.
If the crack didn't go around a corner like that, I'd say pinning it has a 95% chance of success. I think I could give a punchers odds I could weld it and save the head. As I said, if it was mine, I'd at least take a shot to fix them.