38 CFR 21.5054: Dates of participation.

(a) General. An individual may participate after December 31, 1976. An individual was not eligible for benefits before July 1, 1977, unless discharged after January 1, 1977, for a service-connected condition. The first date on which an individual on active duty enrolled in a course, courses or a program of education leading to a secondary school diploma or equivalency certificate may receive benefits is subject to the eligibility requirements of § 21.5040(f)(4) and (5).

(b) Termination of right to begin participation. (1) Except as provided in paragraph (b)(3) of this section, no individual on active duty in the Armed Forces may initially enroll after June 30, 1985.

(2) An initial enrollment occurs when a serviceperson who has never contributed to the fund—

(i) First makes a lump-sum payment to the fund, or

(ii) First authorizes an allotment to VA for deposit in the fund. See 32 CFR 59.3(b)(10).

(3) Notwithstanding the provisions of paragraph (b)(1) of this section, any individual on active duty in the Armed Forces who was eligible to enroll on June 30, 1985, may enroll at any time during the period beginning on October 28, 1986, and ending on March 31, 1987.