(a) Subdivision (a) of Section 31615 does not apply to a sale, delivery, or transfer of firearms if both of the following requirements are satisfied:
(1) The sale, delivery, or transfer is to an authorized representative of a city, city and county, county, or state government, or of the federal government, and is for the governmental entity.
(2) The entity is acquiring the weapon as part of an authorized, voluntary program in which the entity is buying or receiving weapons from private individuals.
(b) Any weapons acquired pursuant to this section shall be disposed of pursuant to the applicable provisions of Section 34000 or Sections 18000 and 18005.