They do. They even go to a specific shop in one of the episodes: The Bone Room.
The Bone Room was famous - within its niche - around the world. Featured on Mythbusters, as well as having several appearances on local news magazines, written up in articles in local and nationwide publications, and listed in guidebooks, The Bone Room was a destination for travelers and one of the must-see places for locals to bring their visiting friends and relatives.
Do they say they’re actual human remains? They make realistic facsimiles specifically for testing things like they test.
They do. They even go to a specific shop in one of the episodes: The Bone Room.
“Meemaw, I’m so glad you came to see me! …wanna go see some human remains?”