Any homestead entryman under the Act of June seventeenth, nineteen hundred and two, known as the reclamation Act, including entrymen on ceded Indian lands, may, at any time after having complied with the provisions of law applicable to such lands as to residence reclamation, and cultivation, submit proof of such residence, reclamation, and cultivation, which proof, if found regular and satisfactory, shall entitle the entryman to a patent, and all purchasers of water-right certificates on reclamation projects shall be entitled to a final water-right certificate upon proof of the cultivation and reclamation of the land to which the certificate applies, to the extent required by the reclamation Act for homestead entrymen: Provided, That no such patent or final water-right certificate shall issue until after the payment of all sums due the United States on account of such land or water right at the time of the submission of proof entitling the homestead or desert-land entryman to such patent or the purchaser to such final water-right certificate.