At least looking at the California bill being considered: musical instruments would be exempted if they had documentation of being sufficiently old, and contained only a small amount of ivory.

Antiques over 100 years old would also be exempted, but only those containing less than 5% ivory by volume. This would seem to ban the sale of a wide variety of antiques and artworks. I'm not sure about the volumes, for example, but I expect it would ban the sale of many Georgian-era hair-on-ivory paintings and ivory portrait miniatures, amongst other things.