First, only guns can be C&R, so there is no such thing as a C&R suppressor, for example.
The C&R status allows certain leeway in shipping and sales, but does not change the laws and regulations about what a licensee may do. An 01 dealer with no SOT cannot buy or sell a machinegun (except as an individual), whether or not it is a C&R. But an 03 licensee can receive a C&R item directly (no dealer needed), even if it is an NFA firearm. In that case, the C&R status preempts the NFA status. As I noted, I legally delivered those machineguns to the buyers. (Had I had to cross a state where they were illegal, I would have shipped them.)