There is no way of knowing all the laws, so be sure to check before a sale. Also, please be aware of the Native American Repatriation Act of 1992 that prohibits the sale of Native American Indian remains on a federal level. Unless somebody wants a felony on their r sum , do not sell Native American remains. I'm referring to the type of specimen which is commonly found in schools and universities, for example. However, the language in several medical regulations which govern transplant organ facilities can be interpreted as being regulatory, and laws protecting gravesites may also apply.
States enact laws to protect their cemeteries.
In Maryland, where I live, the Annotated Code makes no bones about the severity of grave robbing. But bones in the ground aren't necessarily a grave and may not be protected by grave robbing laws. So ruled the Utah Court of Appeals last year when James Redd, the sole doctor in the small town of Blandings, Utah, was charged with abusing or desecrating a dead human body, a felony, when a hiker spotted Redd and his wife digging up human bones. But bones were not their prey. Near the town of Bluff, at a place called Cottonwood Wash, the couple was digging for Indian artifacts at a ceremonial kiva site used by the Anasazi people perhaps 1500 years ago.