Let's go to the source instead of just guessing:
27 CFR 178.125
(f) Firearms receipt and disposition by licensed collectors. Each
licensed collector shall enter into a record each receipt and
disposition of firearms curios or relics. The record required by this
paragraph shall be maintained in bound form under the format prescribed
below. The purchase or other acquisition of a curio or relic shall,
except as provided in paragraph (g) of this section, be recorded not
later than the close of the next business day following the date of such
purchase or other acquisition. The record shall show the date of
receipt, the name and address or the name and license number of the
person from whom received, the name of the manufacturer and importer (if
any), the model, serial number, type, and the caliber or gauge of the
firearm curio or relic. The sale or other disposition of a curio or
relic shall be recorded by the licensed collector not later than 7 days
following the date of such transaction. When such disposition is made to
a licensee, the commercial record of the transaction shall be retained,
until the transaction is recorded, separate from other commercial
documents maintained by the licensee, and be readily available for
inspection.
The record shall show the date of the sale or other disposition of each firearm curio or relic, the name and address of the person to whom the firearm curio or relic is transferred, or the name and license number of the
person to whom transferred if such person is a licensee, and the date of
birth of the transferee if other than a licensee. In addition, the
licensee shall cause the transferee, if other than a licensee, to be
identified in any manner customarily used in commercial transactions
(e.g., a driver's license), and shall note on the record the method
used. In addition, the licensee shall--
(1) Cause the transferee, if other than a licensee, to be identified
in any manner customarily used in commercial transactions (e.g., a
driver's license), and note on the record the method used, and
(2) In the case of a transferee who is an alien legally in the
United States and who is other than a licensee--
(i) Verify the identity of the transferee by examining an
identification document (as defined in Sec. 178.11), and
(ii) Cause the transferee to present documentation establishing that
the transferee is a resident of the State (as defined in Sec. 178.11) in
which the licensee's business premises is located if the firearm curio
or relic is other than a shotgun or rifle, and note on the record the
documentation used or is a resident of any State and has resided in such
State continuously for at least 90 days prior to the transfer of the
firearm if the firearm curio or relic is a shotgun or rifle and shall
note on the record the documentation used. Examples of acceptable
documentation include utility bills or a lease agreement which show that
the transferee has resided in the State continuously for at least 90
days prior to the transfer of the firearm curio or relic.