As I understand it, it's the potential customer who is the primary source of advice here; i.e. the customer is asserting that by using your bank as an agent it would not be required to register as an MSB. I simply do not believe that's true. Whether your bank has a state or a national charter is irrelevant.
MSBs are required to register and disclose their agents; they are not exempt from registration because they have agents. In the 3 or 4 states where I looked at MSB registration requirements in detail at one point, if the MSB has agents in that state the MSB must register in that state. I'm willing to go out on a limb and say that most states probably have similar requirements.
You got rlcarey's gut reaction. Mine is not based on a specific fact situation and it already appears in the thread he linked. I suggest you call both your state and federal regulators and run your customer's scenario and its advice past them. Sometimes it's our job to train our superiors. I will acknowledge that mine never really appreciated my efforts...