There is currently a Federal lawsuit on the matter. The Amish do not have photo ID for religious reasons. So they can not buy from an FFL holder. Some Amishman has filed suit against the ATF, since it is a religiously based issue.An Amish man can't buy from an FFL because an FFL is not an entity (e.g. a person or store).
Sorry, OCD attack.
I hold an FFL03, and I don't know of regulation preventing a sale* if I record the required information and verify the buy is who they claim to be.
* I'll claim ignorance here if there is one.