The horizontal column location is critical for correctly decoding the numbers. There are 7 items possible with the first item listed directly below the first letter of the rear axle code, or column number 15 and the column number is how they will be designated below. The Fremont, CA. plant apparently had their own method of labeling these options as many times they used numbers such as 2 , 4, 5, and sometimes a letter that did not correspond to the other plants. The meaning of these "other" numbers/letters is unknown.

C-15 (G) ~ Power Steering Option Code:
  1 = Power steering [RPO N40]

C-16 (H) ~ Power Brake Option Code:
  1 = Power Brake [RPO J50]

C-17 (I) ~ Radio Option Code:
  3 = Radio [RPO U63 or U69 or U79]

C-18 (J) ~ Disc Brake Option Code:
  3 = Disc brakes [RPO J52]

C-19 (K) ~ Air Conditioning Option Code:
  1 = Four-Season Air Conditioning [RPO C60]

C-20 (L) ~ Power Window Equipment Option Code:
  3 = Power windows [RPO A31]

C-21 (M) ~ Power Seat Equipment Option Code:
  3 = Four-way seats [RPO A42]