(a) Nothing contained in this chapter shall be construed to repeal or modify any law authorizing the acceptance of devises, bequests, or gifts to the United States for their own use and benefit or for any particular purpose specified by the donors or testators.

(b) Whenever the United States receives property and it appears that it is, or shall have been, the intention of the testator or donor that such devise, bequest, or gift be for the benefit of those persons described in section 8301 of this title, or any particular hospital or other institution operated primarily for their benefit, such property or the proceeds thereof shall be credited to the General Post Fund, and shall be used or disbursed in accordance with the provisions of this chapter.