I’d envision some sort of lab that would take samples of the kind that could be scraped off a hidden area with a knife, if it had to be done.
If it’s part of an antique then it’s reasonable to presume it’s antique itself.
I learned piano on a piano that had actual ivories. There is something to be said for the touch. The porosity tends to absorb small amounts of moisture. Sweaty pianist fingers on a modern plastic keyed instrument can build up to a slippery, grimy problem.
If the any governmental entity in the US was required to pay fair value to the property owner for ANY taking of private property or private property rights...for the common good as it is usually described...it would happen far less and only for more important reasons.
DK
I have a sterling chocolate set from the mid-1800s with an ivory heat protector on the handle. It was used to protect fingers from the hot contents. Since it is post-late 1700s, it would be illegal, even though it is a legitimate antique.