“(a)(1) Except as provided in paragraph (2), the amendments made by subsections (a) and (span) of section 101 [enacting this chapter] shall become effective on April 1, 1981.
“(2) The provisions of sections 1508, 1512, 1516, 1518, 1519, 1520, and 1521 [now 3108, 3112, 3116, 3118, 3119, 3120, and 3121] of title 38, United States Code, as added by section 101(a), shall become effective on October 1, 1980.
“(3) Notwithstanding paragraph (2), the provisions of chapter 31 of title 38, United States Code, as in effect on the day before the date of the enactment of this Act [Oct. 17, 1980] (other than section 1504, relating to subsistence allowances, and section 1507, relating to loans [former sections 1504 and 1507 of this title, respectively]), shall continue in effect until March 31, 1981.
“(4) Effective on October 1, 1980, sections 1504 and 1507 [former sections 1504 and 1507 of this title] are repealed. During the period beginning on October 1, 1980, and ending on March 31, 1981, the provisions of sections 1508 and 1512 [now 3108 and 3112] of title 38, United States Code, as added by section 101(a), shall apply to veterans pursuing a program of vocational rehabilitation training under chapter 31 of such title in the same manner as sections 1504 and 1507 of such title, respectively, applied to veterans pursuing a program of vocational rehabilitation training under such chapter on September 30, 1980.
“(5) Subsection (c) of section 101 [enacting provisions set out as a note under section 3108 of this title] shall become effective on October 1, 1980. Subsection (d) of such section [enacting provisions set out as a note under section 3107 of this title] shall become effective on the date of the enactment of this Act [Oct. 17, 1980].”