This part prescribes regulations to assure the granting of preference to blind persons licensed under the provisions of the Randolph-Sheppard Vending Stand Act (49 Stat. 1559, as amended by the act of August 3, 1954, 68 Stat. 663; 20 U.S.C. 107) for the operation of vending stands (which term as used in this order includes vending machines).