Soybomb, you've got something crossed yourself:
"but there is no legal requirement that it be mailed from a ffl"
Maybe you just misspoke and meant to say "shipped?"
Actually, a nonlicensee can ship a handgun to a FFL (UPS, FEDEX, etc.) but he cannot mail a handgun.
There is a reason the following language is on the Form 1508:
"The undersigned is a manufacturer of firearms or bona fide dealer therein, and the parcels presented for mailing herewith are customary trade shipments or other articles for repair or replacement of parts. To the best of my knowledge and belief, the addresses are manufacturers of firearms or bona fide dealers therein."
"A nonlicensee may not transfer a firearm to a non-licensed resident of another State. A nonlicensee may mail a shotgun or rifle to a resident of his or her own State or to a licensee in any State. The Postal Service recommends that long guns be sent by registered mail and that no marking of any kind which would indicate the nature of the contents be placed on the outside of any parcel containing firearms. Handguns are not mailable. A common or contract carrier must be used to ship a handgun."
[18 U.S.C. 1715, 922(a)(3), 922(a)(5) and 922 (a)(2)(A)]
ricless 
