27 C.F.R. § 478.94
A licensed importer, licensed manufacturer, or licensed dealer selling or otherwise disposing of firearms, and a licensed collector selling or otherwise disposing of curios or relics, to another licensee shall verify the identity and licensed status of the transferee prior to making the transaction. Verification shall be established by the transferee furnishing to the transferor a certified copy of the transferee's license and by such other means as the transferor deems necessary: Provided, That it shall not be required (a) for a transferee who has furnished a certified copy of its license to a transferor to again furnish such certified copy to that transferor during the term of the transferee's current license, (b) for a licensee to furnish a certified copy of its license to another licensee if a firearm is being returned either directly or through another licensee to such licensee and (c) for licensees of multilicensed business organizations to furnish certified copies of their licenses to other licensed locations operated by such organization: Provided further, That a multilicensed business organization may furnish to a transferor, in lieu of a certified copy of each license, a list, certified to be true, correct and complete, containing the name, address, license number, and the date of license expiration of each licensed location operated by such organization, and the transferor may sell or otherwise dispose of firearms as provided by this section to any licensee appearing on such list without requiring a certified copy of a license therefrom. A transferor licensee who has the certified information required by this section may sell or dispose of firearms to a licensee for not more than 45 days following the expiration date of the transferee's license.
27 C.F.R. §478.94
Approved by the Office of Management and Budget under control number 1140-0032