Article points out a good point, if you want to get the designs out there, print them out in a book and send them. That is the “loophole” around the issues with posting up the 3D printed design. This is how PGP got around the encryption export laws (can you imagine if we where still limited to DES now, nothing would be secure). They printed out the code in a book and went with the 1st amendment.
http://www.theregister.co.uk/2013/05/14/3d_print_gun_export_laws/