It probably wasn't scanned ( although there are 3D scanners ), it was probably constructed from several modelled parts created in a CAD ( Computer Aided Design ) program then assembled.
CAD models can be scaled to different sizes but if you're 3D printing them the volume of your printer will be a limiting factor.
3D printers for home use generally use a plastic ( PLA, ABS etc ) but there are 3D printers that can create metal models, very expensive though.
Before anyone asks, you can't buy a 3D printer, print a 3D printer and return the original