A guy I work with (has a large practice in our firm) had to go to freakin' NYC to sign in an antique Steinway. No ivory is used in pianos newer than like 50 years old. So all old pianos have legit ivory. Yet he had to drive to NYC and stand around for this, wasting his time. The officious people could have figured out that Steinways of a certain age can come in without this kind of abuse of a person's time. These things can be handled by proper procedure. No I think Ivory is not something we want in the US and yes, there is a small amount, relatively, used in old pianos
There should be certs and forms by known luthiers to show that their wood is Indian palosanto, not Brazilian and that should be acceptable to importation rules, when filed properly. Build a guitar, register a number for the wood you used, and the build of the guitar. Put into a computer. have a stamp inside that can be scanned.