New Jersey Statutes:
2C:58-3. Purchase of firearms.
a. Permit to purchase a handgun. No person
shall sell, give, transfer, assign or otherwise
dispose of, nor receive, purchase, or otherwise
acquire a handgun unless the purchaser, assignee,
donee, receiver or holder is licensed as a
dealer under this chapter
or has first secured a
permit to purchase a handgun as provided by
this section.
b. Firearms purchaser identification card.
No person shall sell, give, transfer, assign or
otherwise dispose of nor receive, purchase or
otherwise acquire an antique cannon or a rifle or
shotgun, other than an antique rifle or shotgun,
unless the purchaser, assignee, donee, receiver
or holder is licensed as a dealer under this chapter
or possesses a valid firearms purchaser
identification card, and first exhibits said card to
the seller, donor, transferor or assignor, and unless
the purchaser, assignee, donee, receiver or
holder signs a written certification, on a form
prescribed by the superintendent, which shall indicate
that he presently complies with the requirements
of subsection c. of this section and
shall contain his name, address and firearms
purchaser identification card number or dealer's
registration number. The said certification shall
be retained by the seller, as provided in section
2C:58-2a.,
or, in the case of a person who is not
a dealer, it may be filed with the chief of police of
the municipality in which he resides or with the
superintendent.
FTF sales are allowed in NJ, but the hoops to jump through would make it not worth it to me. If the buyer works at a dealer, I too would just use the dealer to transfer it. If a FTF sale, it appears as if you have to complete the Certificate of Eligibility form and file it with the local LEO agency:
http://www.njsp.org/info/pdf/sp-634.pdf
IANAL and thankfully not a NJ resident!