Well i'm not sure if the guy is a engineer or not, it could be the guy just has a machince shop. it's not just a brazer, it's the process of brazing. I know all about brazing, heat treating, quenching, etc.. for that's what i do for work. i have even tested brazing process for CCH and metalious using RF induction generators.
hardness tester are used for specfic applications where the hardness is critical. one job i worked on was breaker boxes have to have a certain hardness to take the switching on & off all the time. from my experience the dots are typical of a hardness test.
see when you heat metal to cherry red the metal becomes soft, using a quench water or oil solution will harden the metal. This process is NOT suited for braze application unless you do multiple heatings. When quenching the housing & braze will cool at different times and tempertures. This leads a braze that will Not adhere to the housing but will look like a good braze joint on the surface.
i found out from Rock & snow about the outsourced cams and the process they were using.
hope this helps