If they offer the service in their shop then they are doing it for a living. Every automotive machine shop I've ever been to do has been filled with "gear heads"...they bled 10w-30 and drank atf instead of coffee in the morning. I guess it takes time to shop around and get a feel for the shops. This was my first Mercedes cylinder head assistance but but no means my first cylinder head job. An aluminum head is an aluminum head. All the shops I've used all offered to disassemble and reassemble. I've used shops in Ohio, Arizona, South Carolina. None yet in Florida.
Theres a difference between a machine shop and an automotive machine shop. My family has had relatives in the machine shop business for many, many years. My father was a tool and die maker for the Big 3. Their shops were not automotive machine shops. They built the tools for the assembly lines that made the cars