Valve job with head gasket replacement?

I had a conversation about a blown head gasket with a guy who owns an auto repair shop. He told me a valve job is in order EVERY time a head gasket is blown because the head of the valve gets hot, warps, and will not seal against its seat. I've replaced head gaskets on engines that have gotten HOT, and never had any problems after the work was performed. Furthermore, a blown head gasket does not always lead to overheating. I've never heard of this before. Any merit to this?