What's the deal here, is the flex section single wall or double? Or is it double wall but s**t quality?

I went to a local parts store to get a new flex welded in and was told that the one on the headers was a double wall. The brand they carried was Bosal, and he said there's no sense in switching it out since they seem to be the same quality. I'm grateful the guy was honest, but is he right or should I go elsewhere? Or just install as is?