I would question the competency of the plater. It is my understanding you get a satin chrome finish in the technique of plating, not in the technique of distressing the metal beforehand. So look at it this way, all they have to do is strip off the chrome that is on the top and bottom plates, which would leave the original finish (anybody can do this at home with a de-chroming kit). Now if it was so that Leica distressed the metal beforehand by bead blasting that would simply leave the original distressed finish wouldn't it? So why do the plating company need to re-distress an already distressed finish? I think you are being given the run around for something they are uncertain of doing.
Steve