I was actually surprised this pipe doesn't have an inner lining. The handyman that replumbed the water lines said it's ok being exposed as long as the bend is gentle. What do I know? I haven't even seen a gas appliance since I was 18.
The Key word being Handyman, He is NOT LICENSED
The National Standard Plumbing Code states you must be licensed to work with potable water lines and waste pipe lines
So I would say your handyman is not licensed to do plumbing let alone give his opinion how to properly install a gas line
