(r) It shall be unlawful for any person to assemble from imported
parts any semiautomatic rifle or any shotgun which is identical to
any rifle or shotgun prohibited from importation under section
925(d)(3) of this chapter as not being particularly suitable for or
readily adaptable to sporting purposes except that this subsection
shall not apply to -
(1) the assembly of any such rifle or shotgun for sale or
distribution by a licensed manufacturer to the United States or
any department or agency thereof or to any State or any
department, agency, or political subdivision thereof; or
(2) the assembly of any such rifle or shotgun for the purposes
of testing or experimentation authorized by the Attorney General.