I'm reading through the cites manual posted above and when I got to the identification section of the manual I wasn't surprised to see that inspectors were directed to take a sample of the wood with a razor blade to inspect with a magnifying glass or microscope. Then each species has specific identifiers that agents are supposed to look for. Here on TGP, the "brazilian rosewood authorities" routinely say that to identify BRW they look for a sweet spicy smell. Guess what the CITES manual says. Exactly the same thing. If they are in fact targeting guitars, its a safe bet that they will be harvesting a sample of wood from your fingerboard, headstock veneer, bridge, back/sides, etc... to look at it and smell it. So if there is suspicion at all, they WILL be causing irreparable damage to the guitar to conduct their tests. They aren't just going to be looking at a finished guitar and scratching their heads looking at pictures. It looks like they will be cutting pieces off to send to labs and inspect on site.