I know this is a bit of a topic deviation... I dug out the Firearms Transaction Record portion of the Federal Law, which I've copied below. At least the first few paragraphs, after this it covers special cases, but feel free to check the source.
Nowhere in this section does it outline any restriction on the transferee with regard to what they may or may not do with the gun, or whether they may or may not already have a plan to dispose of the gun at the time of the transfer.
If you can find actual law that says otherwise, I would be very happy to see it.
TFred
Federal Firearms Regulations Reference Guide (2005)
Starting on Page 63:
§ 478.124 Firearms transaction record.
(a) A licensed importer, licensed manufacturer, or licensed
dealer shall not sell or otherwise dispose, temporarily or
permanently, of any firearm to any person, other than another
licensee, unless the licensee records the transaction on a
firearms transaction record, Form 4473: Provided, That a
firearms transaction record, Form 4473, shall not be required
to record the disposition made of a firearm delivered to a
licensee for the sole purpose of repair or customizing when
such firearm or a replacement firearm is returned to the person
from whom received.
(b) A licensed manufacturer, licensed importer, or licensed
dealer shall retain in alphabetical (by name of purchaser),
chronological (by date of disposition), or numerical (by
transaction serial number) order, and as a part of the required
records, each Form 4473 obtained in the course of transferring
custody of the firearms.
(c)
(1) Prior to making an over-thecounter transfer of a firearm to
a nonlicen- see who is a resident of the State in which the
licensee's business premises is located, the licensed importer,
licensed manufacturer, or licensed dealer so transferring the
firearm shall obtain a Form 4473 from the transferee showing
the transferee's name, sex, residence address (including county
or similar political subdivision), date and place of birth;
height, weight and race of the transferee; the transferee's
country of citizenship; the transferee's INS-issued alien
number or admission number; the transferee's State of
residence; and certification by the transferee that the
transferee is not prohibited by the Act from transporting or
shipping a firearm in interstate or foreign commerce or
receiving a firearm which has been shipped or transported in
interstate or foreign commerce or possessing a firearm in or
affecting commerce.
(2) In order to facilitate the transfer of a firearm and enable
NICS to verify the identity of the person acquiring the
firearm, ATF Form 4473 also requests certain optional
information. This information includes the transferee's social
security number. Such information may help avoid the
possibility of the transferee being misidentified as a felon or
other prohibited person.
(3) After the transferee has executed the Form 4473, the
licensee:
(i) Shall verify the identity of the transferee by examining
the identification document (as defined in § 478.11) presented,
and shall note on the Form 4473 the type of identification
used;
(ii) Shall, in the case of a transferee who is an alien legally
in the United States, cause the transferee to present
documentation establishing that the transferee is a resident of
the State (as defined in § 478.11) in which the licensee's
business premises is located, and shall note on the form 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; and
(iii) Must, in the case of a transferee who is a nonimmigrant
alien who states that he or she falls within an exception to,
or has a waiver from, the nonimmigrant alien prohibition, have
the transferee present applicable documentation establishing
the exception or waiver, note on the Form 4473 the type of
documentation provided, and attach a copy of the documentation
to the Form 4473.
(iv) Shall comply with the requirements of § 478.102 and record
on the form the date on which the licensee contacted the NICS,
as well as any response provided by the system, including any
identification number provided by the system.
(4) The licensee shall identify the firearm to be transferred
by listing on the Form 4473 the name of the manufacturer, the
name of the importer (if any), the type, model, caliber or
gauge, and the serial number of the firearm.
(5) The licensee shall sign and date the form if the licensee
does not know or have reasonable cause to believe that the
transferee is disqualified by law from receiving the firearm
and transfer the firearm described on the Form 4473.