If you make an SLR and only ASSEMBLE it in Japan or Germany, the simple fact is that more than 50% of the components are still from China or taiwan or wherever. Therefore the COO would still be China, Taiwan, etc.
COO is not needed all the time during import export. But for sensitive products, it will be needed. An example is if you ship garments to USA. Due to import quota, COO is required.
I have heard of how people get around the "made in xxxx" and i have seen fake COOs. So it is not that bulletproof a system. But if caught, penalties are high.
If you make an SLR and only ASSEMBLE it in Japan or Germany, the simple fact is that more than 50% of the components are still from China or taiwan or wherever. Therefore the COO would still be China, Taiwan, etc.