Interesting thing is that more or less the same applies to electronic schematics, that's why companies no longer add them to service manuals as the connections between components can be freely copied. Only thing that you can copyright is the layout or PCB traces, but not as a schematic but as painting. There is an exception if a certain component configuration is patented, but that's rare. So essentially you can copy any electronic device provided you will not use the same layout and traces. * I am not a lawyer, just my personal research