of the Interior is authorized to accept title to any non-Federal lands, interests in lands, buildings, or other property, real or personal, within the authorized boundaries of the Glacier National Park
, as now or after August 8, 1946
, established, when the acquisition by exchange of such property would, in his judgment, be in the best interests of the United States. In exchange for the non-Federal property so to be acquired, the Secretary of the Interior is authorized to convey to the grantors of such property, or to their nominees, any federally owned lands, interests in lands, buildings, or other property, real or personal, within the authorized boundaries of the Glacier National Park, located in the State of Montana and administered by the National Park Service, which are of approximately equal value, as determined by the Secretary, to the property being acquired. In order to facilitate the making of such exchanges, the Secretary of the Interior may enter into agreements for the reservation in conveyances to the United States, or for the grant in conveyances from the United States, of such estates for years, life estates, or other interests as may be consistent, in his judgment, with the accomplishment of the purposes of this section, but all such limitations shall be considered in determining the equality of the interests to be exchanged.