On the Kardex for a car you can find a code that usually is found in the exterior paint code box, but seems to apply to the interior color in the next box.There is also a secondary code for fabric type.
Primary code for color:
A = rot / red
B = schwarz / black
C = braun / brown
D = beige / beige
F = blau / blue
G = grun / green
K = fawn
Secondary code for fabric type:
C = corduroy
P = pepita / hound's tooth
Leder = leather
Kunstl. or K'Leder = leatherette
This coding form applies from 1965 through 1968 model years for both 911 & 912.