Notwithstanding the provisions of title 5, Executive order, or administrative regulation, an Indian tribe or tribal organization carrying out programs under the Indian Self-Determination and Education Assistance Act (25 U.S.C. 5301 et seq.) or the Tribally Controlled Schools Act of 1988 (25 U.S.C. 2501 et seq.) or an urban Indian organization carrying out programs under subchapter IV of this chapter shall be entitled to purchase coverage, rights, and benefits for the employees of such Indian tribe or tribal organization, or urban Indian organization, under chapter 89 of title 5 and chapter 87 of such title if necessary employee deductions and agency contributions in payment for the coverage, rights, and benefits for the period of employment with such Indian tribe or tribal organization, or urban Indian organization, are currently deposited in the applicable Employee’s Fund under such title.