does this exhaust maniold look cracked or destroyed or am i ok?

[chewychevy67]

Passenger side 67 small block. I Needed to heat up the center smog port plugs pretty hot to get them out. I don't recall if it looked like this or not before heating but pretty sure it didn't. It looks like squares in the manifold where the rest looked like even cast. Would this be weak now? I am going to get these ceramic coated but don't want to waste my time on a bad one. your thoughts? any way to check it without putting it on an engine? Rod.