If your car is a green 1969 it will be Almond green, unless the colour has been changed at some point to a non-standard colour. If so, the paint code won't be on the car!
The third letter of the chassis number shows the colour, but not the exact shade eg
A - Black
B- Light grey
C-Dark red
D-Dark blue
E-Mid green
F-Beige
G-Brown
H-CKD Finish
J-Dark grey
K-Light red
L-Light blue
P- Ivory
R-White
S-Mid grey
T-Light green
U-Dark green
The BMIHT Heritage Certificate will show the colour of your car but you have to pay for one. The most likely colour is Almond Green which was used from 1961-1970, BMC code GN37, ICI code 3480. Also used was Connaught Green from 1969-1970, BMC code GN18, ICI code 3302.
That is what my list says but it could be wrong. I will check up on that one - Cheers
Just checked a couple of books and its not there so I will ammend my list