As the popularity of ferrets as pets has gone up, more and more breeders are having the procedure done

The number one breeder in the U.S. is Marshall's, and the ferrets they don't sell to testing labs are descented for sure

And keep in mind, that the removal of the scent glands doesn't make them completely scent free, they'll still smell like a little animal (because duh), and if you don't maintain their living environment, they will make it smell just like a dog or cat would