1974 is first yr I ever found of rally wheel mentioned in sales brochures for 4x4. Not sure about 2wd. Lower RH corner makes mention of rally wheel.
Funny note, there is early and later rally wheel in 4x4.
74-76 first design was 15x7 with optional 15x8 rally wheel. 15x8 was standard by '77 or so says parts book.