The Commission may acquire lands for the purposes described in §§ 5-118, 6-101 and 6-102 of this article outside the metropolitan district in Montgomery County and in Prince George's County, but within the Maryland-Washington Regional District in those counties, if the Commission finds within the exercise of its discretion that the acquisitions are necessary to preserve any portion of the Commission's regional park plan for the metropolitan district in Montgomery County and Prince George's County, respectively, which plan is a part of the Commission's general plan for the physical development of the Maryland-Washington Regional District. The Commission may expend, for the foregoing purposes, any current funds which under the provisions of this article are authorized to be expended for land acquisitions in the respective counties within the metropolitan district for the purposes authorized by this section, and the funds which may be so expended by the Commission in that portion of the Maryland-Washington Regional District known as the Upper Montgomery County Metropolitan District may include the proceeds of bonds issued by the Commission under § 6-102 of this article.